Ludum Dare (from Latin "to give a game") is a game development competition where the participants have 48 hours to create a game. All of the code and content must be created during the 48 hours, each entry must be created by a single person and source code must be shown.
This year's theme was "Tiny World" and had 1402 submissions. Phew! But there can only be one winner, "Fracuum" by TylerGlaiel.
Some runner-ups, worth looking at titles are Inside My Radio, Super Strict Farmer and Extensionism.