My neighbor works for an orthodontist and I asked if she could get me some of those little rubber bands that kids put on braces. I originally wanted them for rod building (you know to hold the guides on while wrapping), but when I saw the colorful selection she got for me I started thinking about flies.
I tied a few midges with the things. Although maybe some look more like tiny caddis larva. Whatever they look like they look good to me (and hopefully to the fish). The pattern is simple, just wrap the little elastic band around the hook (these are size 20) and you have an instant segmented body. Finish with a thread head and call it done.