Magic: The Gathering, with its power to summon high school social ostracism, is now available for a mere $5 (400) on XBLA to gold members. Football quarterbacks and members of the Young Republicans can now participate or learn the monumentally successful card game in relative anonymity and at a great price -- especially if you factor in the cost of the real card game. Veterans may find the well-crafted XBLA version to be for "beginners," due to its lack of fully customizable decks, but there is an incredible amount of value stacked in there for $5.
Another great and relatively overlooked feature is the game's two-player co-op, which allows you to cut a spouse or friend into the deal. Once all the social stigma is stripped away, it's pretty easy to see why the game has had the staying power of a Drudge Skeleton.