Just remember, no one even remotely related to CBS or the show itself is eligible. Nor--and this clause is kind of odd--is anyone hoping to run for public office, as they'll have to hold off on their campaign until after the show airs. Also, if you're crazy, they say you shouldn't bother showing up, as they do a thorough physical and mental health check on the applicants.
But anyone who has watched past seasons of the show knows that they always let a few crazies slip in. So what the hell! Go on down!