Metal Gear Awesome two, the scene of Gray Fox. That had laughing so hard I couldn't breath.
There's a Sonic parody video that talks about taking things from Newgrounds and putting it up on Youtube. People are doing that more in their Newgrounds videos so when people take them for Youtube, they look really stupid. At least with some of the Brawl taunts 2, the people asked first and got permission.
Speaking of doing such things, this guy did smething like that!
http://www.youtube.com/watch?v=dL30lU26egwBut it's still funny, so no one will ever complain.