You can spend hours on this site. There are full CD downloads, some full movie downloads, amazing self-made videos, TV shows, your favorite music videos, how-to tutorials. This site has everything and is highly addictive. You can use it for both educational purposes and frivolous purposes. Either way is fine!
One major con:
-Read the comments below the video(s) at your own risk. They can be very rude and nasty. It's best to either block them and/or ignore them. Makes the YouTube experience much more fun if you don't read the comment section.