The Mining Software Repositories 2011 (co-located with ICSE) conference is hosting the annual challenge in mining data from software repositories. This time there are 2 problems to consider, one is the Netbeans & Eclipse (IDEs) and another is Chrome & Firefox (Browsers). They are providing CVS and bugzilla data for both the projects. It would be interesting to see how the browsers compare with respect to severe security bugs and their fixes. For more information check out the challenge site.