These used to be my favourite pair of knee socks. I darned the holes in them devotedly and stretched their life as long as possible, until finally the holes just couldn't be patched anymore. So I cut the feet out and crocheted onto the ends, creating long, fingerless gloves that go all the way up to my elbow.
I picked up this white sweater at a thrift store and was sad when I got a rust stain on it that wouldn't come out.
I cut the sleeves off at the seam, chopped off some extra material I didn't need, cut the collar out of the top of the sweater, chopped the collar in half and sewed a half on to each sleeve to create a cuff and ended up with a pair of Fame-worthy leg warmers (and immediately gained 80's super powers of being able to frizz people's bangs and working 'like totally for sure!' into conversations).
After performing a vigorous and sweaty dance routine in a big warehouse space, I did yoga in them this morning.
What I really like about these projects is that they add an extra layer of warmth to my extremities. When it comes to cutting back on heating use I believe one of the most efficient things you can do is heat the person, rather than the space, and the simple addition of these two items of clothing do a surprisingly good job of just that.