The kids are really enjoying Sketchfu. It is an online app that allows them to draw a picture and then playback the process, thereby creating an online animation. These animations can be downloaded as pictures or embedded and played back. Be aware however that there are some issues regarding embedding the player in wikispaces and wordpress. You may want to opt for embedding a linked picture instead.
If you have younger kids or teach primary aged students, this may prove to be a powerful storytelling tool. An account is required however.
I am including an example below which my son did the other night.
Learn how to draw cartoons, comics, and anime at Sketchfu!