Ludum Dare - A game development competition

The Ludum Dare competition is a competition where you have to develop a game within 48 hours. As if that wasn't enough, you also have to keep the game within some boundaries. You have to keep the entry relevant to the round's topic and you have to develop the game from scratch. (I'm pretty sure that means you have to write the engine as well, so no Game Maker.)

Personally, I find this really interesting. I usually begin working on a game and then I get tired or bored and begin to play some other games. Usually this is because I don't have to finish the game anytime soon. The 48-hour deadline would definitely help me with that.