Run Newton OS on an iPad
How’d you like to run Newton OS on your iPad? You can with an emulator, and it actually runs on your iPhone, iPod touch, and Mac OS X too. This is all done through an open source project called Open Einstein which now has a working iOS port. It’s not exactly an easy achievement, but if you’re dedicated and can find yourself a Newton ROM image, you can pull it off.
Apparently the emulator runs at about half the speed of a real Newton, and is a bit buggy, but just the fact that you can do this is pretty interesting. You can check out a video of the Newton OS emulator running on an iPad over at Flickr, which is also where the above picture is from.