I took part in the 24th Ludum Dare competition last weekend and produced a computer game in 48 hours (well, more like 15 hours - I had to sleep, eat, celebrate my birthday, and perform in two improv comedy shows at the Idiot Box). The theme (revealed Friday night at 9pm) was Evolution.
I've now rated around 40 of the other games, and there's a huge variety of ideas, themes, game styles, and choices, and also skill levels at putting games together. I've gotten some nice comments from mine; like a lot of my stuff, art isn't the strong part (especially with only 48 hours to work), but the gameplay is pretty fun. Give it a try if you like; it's at:
http://planktongames.com/ld24
The Ludum Dare page for my game is here.