If you like to doodle, and you have a Nintendo DSi I strongly suggest checking out Flipnote Studio. It is a flip-book animation program that lets you have some doodling fun, and then you're able to share your beautiful drawing with other DSi users. And with the DSi's built-in microphone, you can also spice up your creations with sounds. This program is available from the DSiWare store and is completely free.
Here's a cute animation that the guys at Aardman created. It gives you a cute glimpse of what Flipnote Studio is all about.