The 2007 MIT Mystery Hunt involved signing a pact with the devil, who led teams on a descent through hell to retrieve the Mystery Hunt coin. The coin was recovered by Dr. Awkward at 2:14am, Sunday, January 14th.
The hunt began with teams gathered in Lobby 7. The Evil Midnight Bombers What Bomb at Midnight announced the hunt would contain 270--no, 271--no 271 ½ puzzles, all in keeping with the first unpardonable activity of gathering the assembled puzzlers into a massive sudoku grid. The motivational speaker Michael Fauntleroy came in to save the day, offering the teams the opportunity to get the coin and win the hunt in a mere 25--no, 15--no, 5 puzzles, if they'd only sign a simple contract with some unreadable fine print.
After nearly all teams found the coin within a few hours of starting the hunt, they realized that by signing the contract, they had sold their collective souls to Michael Fauntleroy Stopheles (M.F. Stopheles, for short) for a mere penny. To get their souls back, they would have to complete his course of videos on how to be really really evil in various fields, and all the puzzles therein. This would raise their Evilometers to a level where they could rise in power for a showdown with the devil.
Along the way, they also had to complete a series of unfortunate events that would show how proficient they were in each of the seven deadly sins. These helped unlock their seven Sin Meters, which each were linked to certain thematic puzzles. Filling their Evilometers to a certain level unlocked a Hell Runaround, which led them on a wild goose chase through the halls of MIT and down into hell. There they received seven Hell Puzzles, all completely unsolvable without an additional instruction page gained by unlocking the appropriate Sin Meters.
Finally, at each stage, the teams received a certificate of their evil achievement. These certificates were used in the final epic battle with the devil, after which the teams regained their souls and triumphed over evil.
The Hunt, as seen by solvers late in the game (the meters and spiral would fill in as puzzles were solved). Solutions are available from the puzzle pages, and the certificates are at the bottom of the page.
The Sin events are not represented on that page, however. They were, in chronological order:
Graph of puzzles solved over time by all teams. (The raw data of unlocked and solved puzzles is available).
Web analysis showing the amount of traffic received at the server over the course of the three-day event.