A couple years back, NASA engineer Mark Rober turned a pair of iPads into Digital Dudz.. The response was so positive, he built an entire product line around it:
For example, there are six available T-shirts, including the frantically moving eyeball, the haunted mansion portrait, the freaky clown eyes, the beating zombie heart, and, for those seeking something less scary, the adorable kitty eyes.
All of these rely on the free Digital Dudz app, which lets you choose the animated eyeballs, heart, or whatever that peek through the strategic hole in the shirt or pouch you buy.
This is perhaps better illustrated than explained, so take a look at Rober's promo video:
Needless to say, the shirts are vastly improved this year, as they allow you to easily Velcro your device in place; no cutting holes or duct-taping required. And if you paid attention during the whole video, you know that Rober recently quit his job at NASA (talk about timing!) to work full-time on Digital Dudz.
The shirts sell for $29.95, while the app is free -- meaning you could potentially use the latter with your own shirt for a free, homemade costume.