Some of you probably already know this, but I just found out the other day and thought I would pass it along.
You can view any video on YouTube in high quality by adding the following onto the end of the URL in the address bar:
&fmt=18
It doesn't make it amazing 1600x1200 500FPS or anything, but it will improve the full screen view on most videos. It may also slow down the download rate, so if you're on a slow connection you may not want to use this.
I don't really know how it works, and there may be better ways to do the same thing, so feel free to add to this.
Oh, some of my favorite YouTube videos are the "Look Around You" series

. Very funny, though not very socially redeeming according to my dad.
Brijar!!!