Phillipe and John's talk on contributing to Eclipse is well worth a read. They cover the process involved in getting a bug fixed in Eclipse, from reporting the original problem, via attempting to locate where the problem is, and then how to check out and test the source code from CVS finishing with contributing a patch to bugzilla. Some excellent advice, including how to converse with committers on the other side of bugzilla and ways of improving patches. As an aside, it's worth knowing the legal process flowchart v1.2.4 behind Eclipse contributions (accessible from http://www.eclipse.org/projects; look for "IP Process Flowchart") .
They also link to several bug reports, which go into an impressive amount of detail in analysis and suggested fixes. Any one of them could be counted as Great Bugs for the Callisto contest (that is, if they were against the Calliso release).
In short, Eclipse is a community. If we can all give and take a little, it makes it a better place for everyone. Annoyed by a bug that hasn't been fixed? Fix it yourself. I'm going to take this advice to heart and start fixing some of the outstanding issues that I've submitted in the past, and this presentation is a great starting point for those who haven't done it before.