Minecraft is the most consuming and compelling environment for me at the moment... playing with my little guildies at Massively Minecraft is a joy! ... and I'm learning so much about how kids connect via games-based communities.
Other games on my desktop at the moment: Tera, Braid, Diablo III, Terraria, Super Meat Boy, Dragon Nest, Rift, WoW, Portal2. And yes I am easily distracted! ;)
I am sometimes active in a couple of guilds, but I must admit I'm a quester at heart and loove exploring new games worlds - currently spending way too much time wandering around Tera ... 'oooo pretty!'