Here is a Halo 3 machinima short from TheDuoGroup, who I happen to be a fan of. They also created a Metal Gear Solid animated short which circulated around the Internet a few months back, and I was very impressed by it.
This new piece is short and simple, but has some very clever visual elements that you don’t often see in Halo machinima, or any machinima at all, really. Great use of some animated elements, and it features a song by Beck, so you know it’s gotta be good.