I'd pulled out these little colored balls of yarn, which are leftovers of what I dyed a few years ago for my color spectrum blanket, and left them sitting on my night stand. They were staring up at me, so I cast on some ribbing in white and set to work making a colorwork hat.
I love hats for this reason....A normal worsted weight hat can be started and finished in a few hours. Sure colorwork takes a bit longer, but you'll still have that wonderful sensation of having completed something without having put too much time into it.
It's already blocking. It just needs ends woven in (and maybe a pom pom), and it's done!