Im not sure why you are getting so many negative comments. For those that are interested in open source, and would be contributing to projects regardless, I think this is a great idea. Also, it sounds like a good way to distract oneself from the normal expectations/disappointment cycle of interviewing

"Doing work for free", as some others have pointed out in a negative light, is fundamental to how modern software works. If you're not contributing then you're profiting off of the minority that does...