Primate Plunge is excellent, but too easy. Very time consuming and hella-addictive, though, I warn you. Don't have a link, but I got it from MacUpdate I think.
I also enjoy playing Encompass, Aquatomic, Snood, and OF COURSE, Glider Pro, which is now officially abandonware, and can be downloaded from the author's website
- takes me back to System 7, that game does.