From dolohov: The first in a series of Cat Mario play-throughs. If you've seen the "Most Difficult Super Mario Mod Ever" videos it's kind of like those. However "Cat Mario" is much more moddy, with new characters and new items that sometimes behave like the originals, and sometimes... very not :) Also this is someone actually playing through the game and recording it as they go, so the comments aren't as extreme or well thought out, but just as amusing in a more under-stated way :)
From tiercel: A link to a post in the Final Fantasy 6 community that in turn links to several FF6 anime intros that people have made, which involve creating new animations featuring FF6 characters and synching them to the openings for existing anime. There's one for FMA, one for Escaflowne, and one for a series i haven't heard of before called "Ouran Host Club."
While looking through the links to those i also found a link to a Dragon Warrior anime opening, set to i'm not sure what. There's probably some other cool stuff hidden in the links, but i'm having a tough time sorting though them since most of them are at least partly in japanese and my skills at reading kana have sadly degraded =P
I did eventually stumble upon some english titled stuff, which included some more normal AMVs such as "Final Fantasy VI Opening" set to the "Terra in Black" OCRemix song. and "Final Fantasy: Dancing Mad", which includes clips from pretty much every FF game in existence, and you can guess what song it's set to :)