Apparently retro video games can make for some cozy casual attire as this tutorial from Instructables user TheGreatS on making a pong-playing T-shirt with a flexible screen demonstrates.

This is my Halloween costume for the year 2013. It’s been in the works for about a year and has taken quite a few man hours to create. The screen is 14 by 15 pixels, so, pretty low resolution but it can still do some fun things. It is physically flexible in all directions, although it cannot be folded without damage. It has a controller consisting of a single button and slide pot, connected to a pro mega via USB. To keep it alive for a long time it employs two monstrous 2200 mAh batteries wired in series to get the necessary voltage, and then a 5 Volt regulator to make it usable. All the electronics are place in pockets on the inside of the shirt so they can be removed and so the shirt can be washed.

[via adafruit]