At the Octagon Global Recruiting booth, fans are given a waiver form and an appointment time. At their appropriate time, they can enter the booth, which has cameras on the ceiling (these appear to feed outside the booth so observers can see what is going on). With a set of headphones and television equipment, participants are shown images and have to say what first pops into their heads. Some of the images are reportedly very bizarre. Questions are then asked such as "You just took away a child's favorite toy. Why?"
The test apparently lasts about five minutes, and upon completion you are told whether you passed or not (its likely everyone will "pass" as part of the ARG). Participants are then told to make sure they see the Lost panel on Saturday, and have their test sheet with them (they apparently make a point of having your own sheet with you).
Source: Lostpedia