Well..if you have a squirrel on hand, I'd say this is pretty epic physics trick that I still don't understand..
I mean..how does he live??
Now this is the coolest trick I've seen yet, but this is definitely not practical. It will most likely not work either, because this was not done just with a cup and water. I'm pretty sure he coated the cup with something to make it work, but it's still cool, right? I just wouldn't try it at home anyways.
But if you actually wanna do something to show friends, this would be pretty cool..Slow. But cool!