Here is a great little game to play.  
It's supposedly aimed at kids but I'm pretty sure that this includes the kid inside us all.  The basic premise couldn't be simpler: draw a series of forms on a page, a continuous line or a jigsaw of shapes, let it flow from the brush/pen whatever, don't second guess, enjoy making the lines, stop before it gets too full.. but don't worry about it.  Next up, get some tracing paper and cut it down to size.  Draw a set of simple eye shapes on them - dots, circles c's etc. Lastly, but not leastly, move the tracing about over the previous shapes and watch the magic happen.  Guaranteed twice as addictive as a baby monkey on a skateboard.

The idea was picked up from the following sources... created by faceheads.ru, posted on drawn.ca by @johnmartz.