Technically not a Macintosh, but made by the same company, I own two original Apples: an Apple ][ (1977), which is functional, and an Apple ][e (1983), which is non-functional at the moment.
I found them laying out on the side of a pawn shop building, and they had educational stickers (School name, phone, unit #, etc.) affixed to them, which have since been removed. They were covered in leaves and debris, and the ][e's keyboard was warped and had missing keys. Later, after bringing them home and opening them up, I discovered leaves INSIDE the computer. I asked the pawn shop owner how much he'd like for them, and he willingly gave them to me for free.
After a thorough cleaning, the ][ boots and I can perform simple BASIC programming on it, but not much more. The ][e has something wrong with it, but is close to functioning. I also got an old Apple 12" monochrome monitor, which looks like it was either part of the ]['s or the ][e's package at the time, and a dual 5 1/4" drive which can be attached to either the ][ or ][e. The monitor doesn't work and I don't have disks to test the dual-floppy drives.
Anyway, that's it. If I absolutely MUST have a Macintosh to participate in this, well, my best friend of 26 years and also neighbor has an original Macintosh 128k and external hard drive that we used to play Dark Castle and TAO (This Ain't Othello) on.