I spent an hour or so last week, on Ravelry and otherwise, searching for knitting projects I could do with yarn I already have. I've gotten to the point where I enjoy knitting for knitting's sake enough that it doesn't matter what I'm working on so much. And it gives me a little high to keep learning new ways to put stitches together and etc., without having to spend a lot of cash to do so.
This particular "scrap yarn" project is the Baby Bonnet from the book Last Minute Knitted Gifts. The yarn is Lamb's Pride worsted (in "kiwi" and "sandy heather"), leftover from this hat I made for Christmas. I don't really know what I'm going to do with it--probably tuck it away for some last minute baby shower gift or some day when we have a wee one--but I learned to make an i-cord in order to finish it. It was a tricksey concept, but, with a little help from the all-knowing internets, I quickly figured out why the "i" stands for "idiot". (As in, even an idiot could figure this out!)
Look for lots more little "stash" projects to come.