If you’ve never heard of it, Ludum Dare (LD) is a game developing event/competition where participants are asked to quickly create a game based on a theme within 2-3 days. The LD community then votes on the submitted games in various categories, and winners are announced. The most recent LD marks the ten year anniversary for the competition, and ended up with a whopping 1,402 entries based on the theme of “tiny world.”
The games vary in quality as both veteran and amateur developers can toss their digital hats in the ring, but most all of the games are short- so even if you end up with a dud, you won’t have to spend too much time with it. Coupled along with the site- where contestants can post updates, post-mortems, and reflections- LD provides a fascinating insight into the basic principles and problems involved in game creating, along with seeing budding developers get their feet wet. Best of all, you can try out all the games for free.
If you’re looking for recommendations, Super Strict Farmer and Planet 161 are quite enjoyable. Also, if you’re looking for more large scale collections done in this vein, previous LDs are availabe through the site, which includes min LDs, TIGSource has a series of great competitions, and the Pirate Kart also has a great selection of quickly made games.