Let's say you came by this video from google tech talks on youtube:


Which is located here: https://www.youtube.com/watch?v=L2SED6sewRw

And you liked it so much that you want it on your drive for future reference or in case you might want to watch it again later. Now all you need to do is just type pwn in front of youtube in your address bar and you will arrive to a download page of that exact video in standard quality(.flv) and high quality(.mp4).

Example:  https://www.pwnyoutube.com/watch?v=L2SED6sewRw

Pretty clever idea and well executed. :)