I'm happy to announce a project of our lab (Algorithmic Biology Lab in St. Petersburg) — a problem solving platform for algorithmic problems in bioinformatics: rosalind.info!
Those who like programming and want to learn some bioinformatics concepts will definitely like it.
It starts with easy programming exercises (for Codeforces people), but comes to some hardcore graph algorithms, dynamic programming, etc. You can both improve your algorithmic skill and learn a whole new area at the same time.
Bioinformatics is fun — try it.