Xbox Europe, but let's be clear: Xbox (likely in a new, fancier form) will be at Gamescom. Xbox community guru Larry "Major Nelson" Hryb reiterated this afternoon that Xbox will return to Gamescom following last year's absence.
Nintendo, which also skipped out on Gamescom last year, will be in attendance for the 2013 show as well.
As for what Microsoft has in store, be sure to check Joystiq on May 21 to find out. But, you know... it's cool if you want to hang out here before then. We've become accustomed to your presence. Want to share a juice box?