Blizzard is leveraging pure nostalgia with WoW Remix: Mists of Pandaria, a limited-time opportunity to rewind time and play through a modernized version of the 2011 expansion. When it goes live on May 16, you'll be able to quickly level up a character who will transfer over to the regular servers when it's over, presumably as a fun way to prepare for The War Within expansion later this year.
WoW expansions are already playable as you level up in WoW, but WoW Remix: Mists of Pandaria will...