Blizzard Entertainment sends word that their next product announcement will take
place Friday, September 20 during this year's Tokyo Game Show. There are no
further details about the planned announcement other that it will involve
back-to-back press conferences, but this should provide fuel for some
interesting speculation, since the TGS is primarily focused on console games,
though Blizzard has shown off PC offerings at the show in the past.
Honestly, given Blizzard's historical rate in releasing products, it seems abnormal to have just released a game and to start another full game this soon with Worlds of Warcraft in development.
My personal guess is the inevitable WarCraft3 expansion.