My computer hasn't yet frozen up completely again, so haven't got those console logs yet - however it did just now lose the Airport network again. Even restarting the computer couldn't bring it back; I had to restart the router (even though it was broadcasting the name of the network just fine).
Because I restarted the computer, I couldn't grab the relevant console.log details, but here is what system.log reported (this may not help you at all, so I will also post console logs following the next freeze-up). The timeframe is from when I started using my computer about 1pm through to returning home to find the network gone (just before 9pm).
Thanks!
Dec 1 13:01:46 OptimusPrime authexec: executing /sbin/kextload
Dec 1 13:02:36 OptimusPrime kernel[0]: disk1: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:03:48 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:15:45 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:15:45 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:15:46 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:15:47 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:15:47 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:15:47 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:33:30 OptimusPrime kernel[0]: disk1: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:32 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:38 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:38 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:45 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:46 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:33:47 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:34:14 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:34:14 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:34:16 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:34:16 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:34:16 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:34:16 OptimusPrime kernel[0]: disk1: alignment error.
Dec 1 13:46:35 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:46:35 OptimusPrime kernel[0]: disk2: ioctl(_IOW,'d',128,16) is unsupported.
Dec 1 13:51:24 OptimusPrime mdimportserver[4300]: StuffIt Spotlight importer: Could not open the archive. Error: 17508
Dec 1 16:03:28 OptimusPrime dashboardadivsoryd[10264]: fetch-parsers: unable to fetch data from read stream
Dec 1 16:03:28 OptimusPrime dashboardadivsoryd[10264]: fetch: unable to fetch data from read stream while fetch advisory list
Dec 1 16:56:06 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 16:56:08 OptimusPrime lookupd[11063]: lookupd (version 369.6) starting - Sat Dec 1 16:56:08 2007
Dec 1 16:56:29 OptimusPrime mDNSResponder: Repeated transitions for interface en1 (FE80:0000:0000:0000:0219:E3FF:FE0F:2093); delaying packets by 5 seconds
Dec 1 16:56:31 OptimusPrime launchd: Server 12327 in bootstrap 1103 uid 0: "/usr/sbin/lookupd"[11063]: exited abnormally: Hangup
Dec 1 16:56:31 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 16:56:31 OptimusPrime lookupd[11068]: lookupd (version 369.6) starting - Sat Dec 1 16:56:31 2007
Dec 1 16:56:33 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 16:56:33 OptimusPrime lookupd[11069]: lookupd (version 369.6) starting - Sat Dec 1 16:56:33 2007
Dec 1 16:56:35 OptimusPrime mDNSResponder: Repeated transitions for interface en1 (192.168.0.2); delaying packets by 5 seconds
Dec 1 17:16:06 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 17:16:08 OptimusPrime lookupd[11283]: lookupd (version 369.6) starting - Sat Dec 1 17:16:08 2007
Dec 1 19:42:31 OptimusPrime launchd: Server 0 in bootstrap 1103 uid 0: "/usr/sbin/lookupd"[11283]: exited abnormally: Hangup
Dec 1 19:42:31 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 19:42:31 OptimusPrime lookupd[12082]: lookupd (version 369.6) starting - Sat Dec 1 19:42:31 2007
Dec 1 20:06:06 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 20:06:06 OptimusPrime lookupd[12656]: lookupd (version 369.6) starting - Sat Dec 1 20:06:06 2007
Dec 1 20:58:43 OptimusPrime authexec: executing /usr/bin/pmset
Dec 1 20:58:43 OptimusPrime loginwindow[79]: sendQuitEventToApp (EyeTV Helper): AESendMessage returned error -1712
Dec 1 20:58:43 OptimusPrime authexec: executing /usr/bin/pmset
Dec 1 20:58:54 OptimusPrime shutdown: reboot by OptimusPrime:
Dec 1 20:58:54 OptimusPrime SystemStarter[12928]: authentication service (12936) did not complete successfully
Dec 1 20:58:56 OptimusPrime SystemStarter[12928]: The following StartupItems failed to properly start:
Dec 1 20:58:56 OptimusPrime SystemStarter[12928]: /System/Library/StartupItems/AuthServer
Dec 1 20:58:56 OptimusPrime SystemStarter[12928]: - execution of Startup script failed
Dec 1 20:59:36 localhost kernel[0]: hi mem tramps at 0xffe00000
Dec 1 20:59:36 localhost kernel[0]: PAE enabled
Dec 1 20:59:36 localhost kernel[0]: 64 bit mode enabled
Dec 1 20:59:36 localhost kernel[0]: standard timeslicing quantum is 10000 us
Dec 1 20:59:36 localhost kernel[0]: vm_page_bootstrap: 512955 free pages
Dec 1 20:59:36 localhost kernel[0]: mig_table_max_displ = 71
Dec 1 20:59:36 localhost kernel[0]: Enabling XMM register save/restore and SSE/SSE2 opcodes
Dec 1 20:59:36 localhost kernel[0]: 88 prelinked modules
Dec 1 20:59:36 localhost kernel[0]: ACPI CA 20060421
Dec 1 20:59:36 localhost kernel[0]: AppleIntelCPUPowerManagement: ready
Dec 1 20:59:36 localhost kernel[0]: AppleACPICPU: ProcessorApicId=0 LocalApicId=0 Enabled
Dec 1 20:59:36 localhost kernel[0]: AppleACPICPU: ProcessorApicId=1 LocalApicId=1 Enabled
Dec 1 20:59:36 localhost kernel[0]: Copyright (c) 1982, 1986, 1989, 1991, 1993
Dec 1 20:59:36 localhost kernel[0]: The Regents of the University of California. All rights reserved.
Dec 1 20:59:36 localhost kernel[0]: using 10485 buffer headers and 4096 cluster IO buffer headers
Dec 1 20:59:36 localhost kernel[0]: Enabling XMM register save/restore and SSE/SSE2 opcodes
Dec 1 20:59:36 localhost kernel[0]: Started CPU 01
Dec 1 20:59:36 localhost kernel[0]: IOAPIC: Version 0x20 Vectors 64:87
Dec 1 20:59:36 localhost kernel[0]: ACPI: System State [S0 S3 S4 S5] (S3)
Dec 1 20:59:36 localhost kernel[0]: Security auditing service present
Dec 1 20:59:36 localhost kernel[0]: BSM auditing present
Dec 1 20:59:36 localhost kernel[0]: disabled
Dec 1 20:59:36 localhost kernel[0]: rooting via boot-uuid from /chosen: A73A9889-25B7-4182-9E8D-9517DA24D76D
Dec 1 20:59:36 localhost kernel[0]: Waiting on <dict ID="0"><key>IOProviderClass</key><string ID="1">IOResources</string><key>IOResourceMatch</key><string ID="2">boot-uuid-media</string></dict>
Dec 1 20:59:36 localhost kernel[0]: USB caused wake event (EHCI)
Dec 1 20:59:36 localhost kernel[0]: FireWire (OHCI) Lucent ID 5811 PCI now active, GUID 0019e3fffe2eed1c; max speed s400.
Dec 1 20:59:36 localhost kernel[0]: Got boot device = IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/SATA@1F,2/AppleAHCI/PRT2@2/IOAHCIDevice@0/AppleAHCIDiskDriver/IOAHCIBlockStorageDevice/IOBlockStorageDriver/WDC WD2500JS-40TGB0 Media/IOGUIDPartitionScheme/Merged_Untitled@2
Dec 1 20:59:36 localhost kernel[0]: BSD root: disk0s2, major 14, minor 2
Dec 1 20:59:36 localhost kernel[0]: CSRHIDTransitionDriver:

robe:
Dec 1 20:59:36 localhost kernel[0]: CSRHIDTransitionDriver::start before command
Dec 1 20:59:36 localhost kernel[0]: HFS: Removed 2 orphaned unlinked files
Dec 1 20:59:36 localhost kernel[0]: CSRHIDTransitionDriver::stop
Dec 1 20:59:36 localhost kernel[0]: IOBluetoothHCIController::start Idle Timer Stopped
Dec 1 20:59:36 localhost kernel[0]: Jettisoning kernel linker.
Dec 1 20:59:36 localhost kernel[0]: Resetting IOCatalogue.
Dec 1 20:59:36 localhost kernel[0]: display: family specific matching fails
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 0
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 1
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 1
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 1
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 1
Dec 1 20:59:36 localhost kernel[0]: Matching service count = 1
Dec 1 20:59:36 localhost kernel[0]: Previous Shutdown Cause: 3
Dec 1 20:59:36 localhost kernel[0]: display: family specific matching fails
Dec 1 20:59:36 localhost kernel[0]: wl0: Broadcom BCM4328 802.11 Wireless Controller
Dec 1 20:59:36 localhost kernel[0]: 4.170.13.1IPv6 packet filtering initialized, default to accept, logging disabled
Dec 1 20:59:36 localhost mDNSResponder-108.6 (Jul 19 2007 11: 41:28)[34]: starting
Dec 1 20:59:36 localhost memberd[42]: memberd starting up
Dec 1 20:59:36 localhost lookupd[43]: lookupd (version 369.6) starting - Sat Dec 1 20:59:36 2007
Dec 1 20:59:36 localhost DirectoryService[52]: Launched version 2.1 (v353.6)
Dec 1 20:59:37 localhost kernel[0]: yukonosx: Ethernet address 00:17:f2:cd:ee:26
Dec 1 20:59:37 localhost kernel[0]: AirPort_Brcm43xx: Ethernet address 00:19:e3:0f:20:93
Dec 1 20:59:37 localhost noip2[65]: Can't gethostbyname for dynupdate.no-ip.com\n
Dec 1 20:59:37 localhost noip2[65]: Can't get our visible IP address from dynupdate.no-ip.com\n
Dec 1 20:59:37 localhost diskarbitrationd[41]: disk0s2 hfs 95352757-F40E-398C-97BD-6850D4D6237C Private /
Dec 1 20:59:38 localhost kernel[0]: Registering For 802.11 Events
Dec 1 20:59:38 localhost kernel[0]: [HCIController][setupHardware] AFH Is Supported
Dec 1 20:59:38 OptimusPrime kernel[0]: IOBluetoothBNEPDriver: Ethernet address 00:17:f2:b6:ae:0c
Dec 1 20:59:38 OptimusPrime configd[39]: setting hostname to "OptimusPrime.local"
Dec 1 20:59:38 OptimusPrime lookupd[76]: lookupd (version 369.6) starting - Sat Dec 1 20:59:38 2007
Dec 1 20:59:38 OptimusPrime configd[39]: bootp_session_transmit: bpf_write(en2) failed: Operation not permitted (1)
Dec 1 20:59:38 OptimusPrime configd[39]: DHCP en2: INIT transmit failed
Dec 1 20:59:38 OptimusPrime diskarbitrationd[41]: disk0s3 msdos 00000000-0000-0000-0000-000000000000 WINDOWS /Volumes/WINDOWS
Dec 1 20:59:38 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: No networks found on channel(s) 11
Dec 1 20:59:38 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Could not find "NETGEAR" on channel(s) 11
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: No networks found on channel(s) 11 13
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Could not find "Hanni’s Computer" on channel(s) 11 13
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "linksys"; not found.
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "OptimusPrime"; not found.
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "Hello"; not found.
Dec 1 20:59:39 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "Bonjour"; not found.
Dec 1 20:59:40 OptimusPrime /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow: Login Window Application Started
Dec 1 20:59:41 OptimusPrime mDNSResponder: Adding browse domain local.
Dec 1 20:59:41 OptimusPrime loginwindow[80]: Login Window Started Security Agent
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Error: Apple80211Scan() failed 16
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Could not find "NETGEAR" on channel(s) 11
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Error: Apple80211Scan() failed 16
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Could not find "Hanni’s Computer" on channel(s) 11 13
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "linksys"; not found.
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "OptimusPrime"; not found.
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "Hello"; not found.
Dec 1 20:59:42 OptimusPrime /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport: Already scanned channels 11 for "Bonjour"; not found.
Dec 1 20:59:59 OptimusPrime launchd[95]: net.sourceforge.tvshows: exited with exit code: 255
Dec 1 20:59:59 OptimusPrime launchd[95]: net.sourceforge.tvshows: 9 more failures without living at least 60 seconds will cause job removal
Dec 1 21:03:13 OptimusPrime configd[39]: executing /System/Library/SystemConfiguration/Kicker.bundle/Contents/Resources/enable-network
Dec 1 21:03:13 OptimusPrime configd[39]: posting notification com.apple.system.config.network_change
Dec 1 21:03:13 OptimusPrime lookupd[183]: lookupd (version 369.6) starting - Sat Dec 1 21:03:13 2007
Dec 1 21:03:24 OptimusPrime configd[39]: target=enable-network: disabled