Some really inspiring clips of what paper prototyping can achieve. If you're doing this kind of thing right now, take a look for some great ideas and inspiration.
If I have to criticise, the use of stop motion animation (which you'll see in some of the vids), while entertaining and clever, don't reflect the true nature of the paper prototype testing process. I'd much rather watch someone facilitating a test than a paper cursor moving round the 'screen'.
Having just run a prototyping training session, I've seen first-hand how designers and developers can dive right into the prototype development process then totally miss the point when it comes to learning stuff from the end user's interaction with it.
10 Effective Video Examples of Paper Prototyping - a series of YouTube videos pulled together by Paul Andrew for speckyboy.com