In case you missed them, photos of an early iPad prototype were revealed yesterday. They are from 2002-2004. It is known that Apple was working on a tablet before they decided to release a phone first instead. This shows how far back Apple was experimenting with the touch interface and how long it must have taken to get all the pinching and tapping and momentum scrolling just right.
A web application from the guys of deviantART. I'm pretty sure I've seen this before somewhere in prototype form. In any case, it's pretty cool, and it's completely done in HTML5, which means that it works on any modern, standards-compliant browser... including the iPad. No Adobe Flash nor any other plugins required.