Visit this DrawAndFoldOver to have some fun drawing with your Wacom tablet! This is actually a game you can play via email to make a collaborative drawing and it's a part of the Campaign for Drawing, another interesting site to check out.
Of course a pen tablet device is not a requirement, but it sure is a lot more fun than attempting this with a mouse.
I've been using a tablet for years and I made the leap when I found that the repetitive mouse-clicking was hurting my arm and hand. The Wacom tablet was a great solution, but there are still a lot of things I use the mouse for. And the pen tablet has never fully replaced my real-world pens and pencils, so I never tire of finding ways to merge good old fashioned drawing skills with digital skills. Maybe that's why I think DrawAnd FoldOver is so cool, I'm getting a kick out of drawing with "classic" virtual Bic pens.