Check out this fun Star Trek iPhone case by AndyC, the simplest mods are always the coolest.
“A decade old Star Trek pin with the pin part broken off many years ago. It’s been super glued to the back of my iPhone case (not to the iPhone)”
AndyC via Make, Crunch Gear
Here are some other cool iPhone cases worth checking out.
Paul Frank Headphones Julius iPhone Case
Gorilla Carbon Fiber iPhone Case