Foldit is an online puzzle video game about protein folding. The game is part of an experimental research project, and is developed by the University of Washington's Center for Game Science in collaboration with the UW Department of Biochemistry. The objective of the game is to fold the structure of selected proteins to the best of the player's ability, using various tools provided within the game. The highest scoring solutions are analysed by researchers, who determine whether or not there is a native structural configuration (or native state) that can be applied to the relevant proteins, in the "real world". Scientists can then use such solutions to solve "real-world" problems, by targeting and eradicating diseases, and creating biological innovations.
Check out the FoldIt guild and Foldit wiki page the for more info.
Source: Wikipedia, "Foldit", available under the CC-BY-SA License.