Hoping people will try this free one, it is an "exquisite corpse" collaborative drawing game. One player draws a head, another a torso and another draws the legs. They are then combined to create a strange franken-drawing:
It can be fun except I seem to end up with random people who draw heads where feet should be (in a bad way) so some smart Glitchen would be an awesome addition.
Here are some old school examples from when the Surrealists were playing around with this technique on paper back in the early 1900s: