Those little plastic bread closures make great bobbins for the ends of knitting and crochet projects waiting to be woven in, spare bits of embroidery floss, etc. You can even label them with pencil.
I ran across this on the Ravelry* forums the other day, and it's been a lifesaver as I'm doing finishing work on a sweater.
*If you knit or crochet and you're not on Ravlery, you should be. Make that two tips. :-)