For future reference, putting yogurt in one's sink to clear a clog will eventually work... but it is totally not worth the mess. Or the smell. Good heavens, the smell. My stomach is still churning at the thought of it.
Next time, I'll just call the campus maintenance crew and get over the fact that some guy will have to traipse through my dirty laundry to get to the sink, that same lovely sink that's conveniently located in my dorm room instead of in the bathroom.