It started out as an April Fools’ Day joke at Thinkgeek years ago, but turned into a real product when Thinkgeek saw so much demand for the iCade, an arcade cabinet-shaped dock for anor that adds real a joystick controller and buttons for gaming.
The iCade normally sells for $99.99 at Thinkgeek, but apparently Bed, Bath, and Beyond has some overstock and is selling them for half-price: $49.99.
The iCade dock comes with a free installation of Atari Greatest Hits, but only one game, Missile Command, is free; the rest of the 99 games are available for in-app purchase, which is a little weak. Also, Thinkgeek has a convenient list of iOS games that are compatible with the iCade dock.
Bed, Bath, and Beyond has the discounted iCade available for $49.99 at their website as of this writing. If you want to skip shipping costs, you could do a search for local stores that still have inventory of the arcade dock.