Draw A Stickman is a short linear story in which you draw a stickman and the environment. The drawings are animated as you draw them and you see your story unfold. It is more of a directed doodling session, in which you get to be creative in the confines of the narrative, than a game. It is an interesting use of doodling as a game mechanic.
If you really want to have fun, play twice and give your stickman some creative tools and outfits for his adventure. They recently added a second episode that you can illustrate and more may be added later.