ARG / MIT Mystery Hunt

The MIT Mystery Hunt is an annual puzzlehunt held on the MIT campus. Teams are required to solve puzzles, the solutions of which help to solve the meta-puzzles, which then help to solve the meta-meta puzzles, and so on. There are also many events that take place on the MIT campus. The goal of the Hunt is to use the solutions to the puzzles to help find a coin of some sort somewhere on the MIT campus. Early Hunts were around 30 puzzles long. They have since grown to be around 100 puzzles long, with 10 to 20 meta-puzzles. The winners of the hunt gain the right to design the next year's Hunt.

The hunt is unique among many puzzle hunts in a few ways. There is no cap on team size, leading to a lot of really large teams participating. Also, most of the puzzles for the past few years have been available online, meaning that people who couldn't go to the MIT campus could still participate.

Hunts often come with a plot to explain why people are going around solving puzzles. Past plots have included a murder mystery, a journey through hell, and a 30(0)th anniversary celebration of the Hunt.

An intro to the Hunt can be found here. The Hunt is held every January during Martin Luther King Jr. Day weekend, beginning at (around) noon on Friday, and running continuously until a team recovers the coin, usually 40 to 50 hours later.

Beware, the example list spoils the solution to many puzzles. If you want to solve them on your own, please don't read it.
The MIT Mystery Hunt contains examples of: