Pencilbox preview video
If you didn't already see it on Not The User's Fault, here's the preview video for my HTML 5 -based, multitouch-interface, comic-drawing webapp. (Now called "Pencilbox" - thanks Googleshng and Ben!)
Not shown in the video: the fact that it's got unlimited undo/redo history; you undo by making a counterclockwise circle gesture with your thumb, and redo with a clockwise circle. Also, your history is backed up to a database on the web server, so you can close the page, reopen it, and not only still have your picture, but still be able to undo stuff.