Over at Ruffles and Stuff, Disney posted a tutorial on how to create a "Not Your Grandmother's Cardigan." I used an old black cardigan, a $1 handkerchief and some vintage buttons I picked up in Alameda. I'm not a sweater person, but I have to say it's a nice little trick to upcycle that sweater you'll never wear otherwise.
I could imagine that, instead of using vintage handkerchiefs, you could also simply sew a collar and front facing using a shirt or dress pattern that's already in your collection. It would be a good way to make use of that scrap fabric that accumulates in your fabric collection.