CUBRID, an open source alternative to MySQL is sponsoring a programming contest at http://www.cubrid.org/cubrid_it.
They are announcing the second online programming contest which starts on June 1, 2011. This time they have prepared much more prizes for the participants.
There is only one SQL problem for which users have to provide the most optimized solution in PHP or Java. This page explains all the rules and other important details of the contest.