Eat Chinese food leftovers straight out of the fridge with your fingers.
Lie on the floor in front of the stereo and sing the same song very loudly 14 times in a row. (Jeff Buckley's version of Leonard Cohen's "Hallelujah") (Warning, this may cause your cat to run and hide under the bed.)
Not brush your hair until noon.
Dance around the living room with a paintbrush in one hand and a screwdriver in the other. Oh, and no pants. (I recommend closing the curtains first.)
Sneak your shopping bags into the house, cut all the tags off, put everything away, and hide the bags and tags in the garbage.