So I realize maybe not everyone knows who Monty Oum is and that's a problem.

Starting with one of his first videos, Icarus:

http://www.gametrailers.com/user-movie/icarus/74358

Now for perhaps his most famous video, the Halo/Metroid crossover, Haloid:

http://www.gametrailers.com/video/haloid-high-resolution/18747

Next up would be his longest running series, Dead Fantasy which pits Dead or Alive and Final Fantasy characters against each other.

http://www.gametrailers.com/video/dead-fantasy-i-hd/26450

http://www.gametrailers.com/video/dead-fantasy-ii-hd/32364

http://www.gametrailers.com/video/dead-fantasy-iii-hd/52656

http://www.gametrailers.com/video/dead-fantasy-iv-hd/52836

http://www.gametrailers.com/video/dead-fantasy-v-hd/53443

I've seen these before. I remember the Haloid one the most, if only because half the comments I read for it were expressing disappointment they didn't make out at the end.