Vodka and Method are facing off in a race to clear Dragon Soul: http://athenelive.com/dschallenge
I love watching things like this - not only is it fun to see the top guilds in the world competing, you can also pick up some great tips scrutinizing their gameplay.
I always pay special attention to the hunters, of course - it's amazing how much you can improve. I only wish Blizzard would organize more of it - I know watching Arena games always helped me a lot; why not PvE-based competitions?
And yes, I know I could always watch boss kill vids... but really, it isn't the same. People doing boss kill vids tend to either be comfortable playing, showing the strat, or showing a messy-ish first kill. This Dragon Soul challenge will be challenging enough for the players to push themselves, but will also rely on excellent execution.
/popcorn time :)