Ludum Dare is an online game jam that runs every April, August and December. It challenges competitors to create a game from scratch over a two or three day period based on a theme. The competition originally started in April 2002, founded by Geoff Howland. It was run on a separate domain until ludumdare.com was created.
There are two events that run simultaneously during Ludum Dare: the Competition and the Jam. Both require a game to be created based on the same theme, but the rules differ from type to type.
The Ludum Dare Competition expects participants to create a game based on a given theme within a forty-eight hour window. Participants must work on their own and develop the game essentially from scratch. The source code has to be provided when the game is posted. Games produced need to be based on the theme.
Unlike the Competition, the Jam gives participants seventy-two hours to develop their game. Participants can choose to work alone or as a group, and the source code does not need to be provided. Games can be based on the theme, but it is not a requirement.
Prior to the actual events, the community decides and votes on a theme. This theme is then revealed at the start of the jam, of which developers can start making the game.
After the time limit has passed, the games go through a two week voting period. Players can rate games based on its aspects of innovation, fun, theme, graphics, audio, humour, mood, overall and community. Developers can also receive a "Cool" rating based on the number of games they provide feedback on.
When the voting period ends, the results are posted, and the games are ranked.