I’ve enjoyed developing quick little games in the past–where “quick” means isolating yourself from the world for a weekend or so and just pound out some code and deliver on a “little” game of some sorts. The reality is I’ve tried this about four times so far where I was at least somewhat successful but I’ve “planned” on doing it far more than that. I just ran across this site though that’s dedicated to this type of game development and these guys have plenty of games up and available for download. Of course, some aren’t all that great but a few are at least interesting and unique. If you’re into this sort of thing, check their site out: Experimental Gameplay Project.