Last year was particularly awesome in that with Drizzle we were able to have students work on projects that made it back into Drizzle. While I have always seen good work created, it has always been hit or miss on whether the student's work has made it back into the project. Last year though we got more code in then ever before and I believe this year will be the same. We have had students go on to jobs thanks to the work they did on Drizzle.
Interning gives you real experience, and it provides resume material which differentiates students who are going on to work in the software engineering field. Working on open source means that you have real experience on your resume, experience that an employer can see. There are many positions open in the Drizzle/MySQL ecosystem and students who have real world experience should have any easy time finding work with the knowledge you will gain from this program.
For Drizzle we have worked out a partial list for this year:
http://drizzle.org/wiki/Soc
Don't see anything you like? I am happy to add new projects or work with students on libmemcached or Gearman.
Are you interested in working on a different project? Apache, Linux, Postgres? Talk to those projects and ask them to either participate or suggest ideas on projects to them.