The Maverick Global Jam dates have been announced for August 27-29.
Jono has already got things rolling by planning an event on Friday, August 27th at A'cuppa Tea in Berkeley:
http://loco.ubuntu.com/events/team/223/detail/
And I've gone ahead and created a Projects page for it on our wiki so we can organize and plan other Jams for the weekend:
https://wiki.ubuntu.com/CaliforniaTeam/Projects/MaverickGlobalJam