Wizards of the Coast will release its first-ever multiplayer-focused booster set, Magic: The Gathering–Conspiracy, on June 6th.  The 15 card booster packs have an MSRP of $3.99, and are packed 36 to a display.
 
The 210-card booster set will include new mechanics to enhance multiplayer play.  We have confirmed with WotC that it will include 65 new cards, 52 of which will be legal in Legacy and Vintage, while 13 cards will not (this is listed incorrectly in some recent solicitation information). 
 
The rest of the cards are returning favorites, with a focus on fostering an environment of deception and treachery.  The set is designed to be drafted with six to eight players, who then break into groups of players for melee style multiplayer games.
 
Wizards Play Network Core and Advanced stores who register by May 7 in the Wizards Event Reporter can sign up to receive promo copies of alternate-art, foil "Magister of Worth" cards to promote booster display sales and draft competitions in their stores.