Some people always have socks on the go and they aren't counted as a part of their ongoing projects. I do that with Washcloths. As previously mentioned, I knit during down times in game. But sometimes, I get to a point where I will screw up whatever it is I am working on if I don't pay close attention so I just start a garter stitch washcloth. They are useful, easy to knit regardless of what I may be doing, and quite a luxury to use if you find a good yarn.
Here is the latest one, done in cotton stash yarn, and ends not yet woven in.