If you have any interest in gaming or genuine competition, and you haven't watched a Starcraft 2 tournament, you are definitely missing out. There is no need to be a serious gamer, there is no need to even know anything about the game; Starcraft 2 is as entertaining as e-sports get, and doesn't require a deep understanding to enjoy.
What makes Starcraft 2 stand out from the rest of the gaming community is the presentation. First and foremost, the commentators at the professional level are nothing short of excellent. They are deep, engaging, and informative without ever getting too complicated. The presentation of the stream is exciting, polished, and viewer friendly. Each game can be as engaging as you desire, from casual to pro.
Anyone with experience in gaming will be able to appreciate the level that these players compete at. At the highest levels of play, there are professional players who make their living by playing Starcraft 2. But the skill level of the players is only a tertiary reason to watch. The balance of the game means that most matches are close and full of drama.
Most professionals belong to groups, or clans. Not only are there rivalries between the clans, but there is a patriotic aspect to the large tournaments. Each nation wants to represent themselves, and every naion wants to compete with perennial favorite, South Korea.
Sound interesting? Google these prominent leagues and tournaments: IGN Pro League, Major League Gaming, North American Star League, TeamLiquid Star League.