My True Friend sweater (still in progress, but I'm very close to the end of the seemingly-endless striped section!!) is in a fingering-weight yarn, and at the end I'm going to have quite a few small balls of yarn left. In fact, over so many years of knitting socks, and fingering-weight shawls, and hats and mitts, I have quite a few ends of balls. Together they would make a pretty nice memory blanket (instructions here), or an Excavation (fringe means no ends to weave in!).
I could also make a pair or two of Happy Scrappy Socks. The socks doesn't solve my problem of having tiny balls of fingering-weight yarn with no nylon or mohair in it, though. I've got a scrappy crocheted blanket in progress, and I just mixed fibres -- wool, cotton, nylon, alpaca, mohair, silk, whatever -- with wild abandon, figuring the blanket wouldn't get much wear (at least not the way a pair of socks gets wear) and could be handwashed when necessary. Isn't the randomness strangely beautiful?