While not something you could fit into your pocket, this "Stella-Tubby" Atari 2600 mod with its 5" LCD screen is a lot more portable than a the traditional console/television setup.

Nonogadi built this system to use built-in joystick and paddle controllers, as well as original joysticks for two players. It can also run on either power adapter or a pair of 9-volt batteries, so you can break one of these out during a road trip or a long flight -- whoever's sitting next to you likely won't appreciate it, though.

The Stella-Tubby is currently up for sale on eBay with a shockingly high $400.00 starting bid. Crazy!

[Via Technabob]