Blizzard CEO Mike Morhaime joined Bill Prady (co-creator of The Big Bang Theory), Felicia Day (The Guild and Dr. Horrible's Sing-a-long Blog), and Wil Wheaton in playing a game of Elder Sign.
Elder Sign is a card game by Fantasy Flight Games based on H.P. Lovecraft's Cthulhu Mythos. The game is part of Tabletop, the real play series that's part of Felicia Day's Geek and Sundry web channel. Sure, it's not an MMO, but it's got Blizzard's CEO involved. It's a tenuous connection, but I'm running with it.