Google are running a "Highly Open Participation Contest" for students age 13 or older who have not yet begun university studies
http://code.google.com/opensource/ghop/2007-8/
Google is pleased to announce this new effort to get young people involved in open source development. We've teamed up with the open source projects listed here to give student contestants the opportunity to learn more about and contribute to all aspects of open source software development, from writing code and documentation to preparing training materials and conducting user experience research.
There are cash prizes and 10 grand prizes of a trip to Google's HQ in Mountain View, California for the winner and their parent/guardian.