It's a rare chance for some of the world's best players to get together and show the crowd their skills. The action, in 3v3 arenas, will be fast-paced and frantic at times, but it's definitely worth taking a look. Even if you don't PvP, there will be a team of casters ranging from old hands like VHell and Azael to newer recruits such as Hoodrych and Lore, to guide you through the action.
And today the teams were announced, too. I'm not going to reproduce the list here, but head over to the official blog and check them out. There's a prevalence of warlocks and shaman, which is notable, and some big names are coming along. Two teams each attend from NA, EU and China, and Korea and Taiwan field one team per territory. The blog gives a bit more detail on each team, their history, their players and such. Who are you rooting for?