Sit everyone in a circle and give each person a piece of paper and a pen.
Each person begins by writing at the top of the piece of paper what they want the next person to draw (eg a tree, a car, etc). They then pass the piece of paper to the person on their left, who then has a go at drawing what the person wrote. They then fold the paper so the next person can only see the drawing (and not the writing). They then write what they think the picture is, and folds the paper so the next person can only see the writing. Think of it like Chinese whispers (but with writing, drawing, writing, drawing, etc).
Obviously there is to be no talking between players about what the drawing is.
When most people are running out of paper, stop the game, throw the paper into the middle, then each person takes a turn to unravel and laugh at the various drawings :)