Then there's all those accessory patterns out there that don't use alot of yarn...right now I'm looking at a drawstring purse that doesn't seem to need that much...(www.knitting.about.com/library/ndrawstringprint.html). There's lotsa free patterns for that sort of thing out there, if you want to do something that isn't a scarf or socks.
And those little accessory things make such nice gifts. My sister doesn't care much for knitting, but asks me to make her stuff like that all the time. =)