If you like plugging all sorts of strange contraptions into your machine's USB ports, here's something for you. We've seen all sorts of "useful" USB powered gadgets: mug coolers and heaters, lights, pencil sharpeners, copressed air missile launchers, vacuum cleaners, so why not a plasma ball?
The device measures 100x100x150 mm (aprox. 4x4x6 inches) and costs a mere $3.98. The ball itself is 3.5 inches in diameter, so if you want your case too look like the Las Vegas Strip as seen by Hunter S. Thompson, you could probably get away with sticking it somewhere inside.
Although than you wouldn't be able to touch it and feel its awesome might at your fingertips.
In case you want one, you can get it here.