For newbs, what's the best way to find interesting projects and get noticed?

So I just started a Master's program for Software Engineering, and so far I'm loving it. The baseline knowledge is good, but I really want to contribute to actual projects in a tangible way, and hopefully learn something new. Given my lack of experience at this point I don't expect that I could find a job, so I'm willing to work for free in exchange for learning something and building a portfolio.<p>But I really don't know where to begin. Any suggestions?