It’s essentially just a marketing tool for the Dark Knight movie, but hot damn if we don’t like this. Just run the app, take a picture of yourself, then add Joker elements to your face. Works on iPhone (use the camera) or iPod touch (use a saved picture). The only downside is that there’s no way to delete picture elements once you’ve let go of your fingers, so be careful or you’ll have to start over. [iTunes - Thanks Marco!]