How about drawing pictures with crayons, make waterpaint pictures, chill out to some Pink Floyd, stare at some trippy colored posters, or play some music?
Kidding, that's very cliche of people to say and I don't personally take to doing one of those activities and find interest in them, acid or no acid.
Hang out with friends, play a fun multiplayer game, walk your dog, have a good dinner. Personally, I like to do things on drugs that I'd be doing anyway, as sober. Really brings out the drug as you notice how different everything is from when you do them sober. Just do whatever you feel like doing. It's not like when your high all the sudden you can't do what you want unless you prepared and had everything within 3 feet of you.
And if you are in such a state, I'm sure coloring or moving is the last thing your worried about.