Educational experience is. None can hold advanced degrees. Students who have been Finalists twice cannot compete. If your team is eligible to compete in a Regional Contest, it is eligible to compete in the Contest Finals. See the individual Regional Contest Rules to determine eligibility in your area.
Rules vary to accommodate different educational systems in different countries.
The contest pits teams of three with one computer against a host of problems in a limited time-frame. These problems can generally be solved by careful analysis and application of algorithms taught in undergraduate computer science. Some are real corkers. See the archives for examples. Practicing for the contest involves cleaning up your computing background and being able to produce under pressure.