Play the scribble game with yourself.

Close your eyes and draw a random squiggle, then turn it into whatever you want! Constraints can include: only draw people, only draw animals, have someone else draw the squiggle, etc. etc.

(Image: Ryan Ottley, http://ryanottley.tumblr.com/post/105206923162/scribble-game-heres-a-new-one-at-the-top