Cool Gadgets for the S4?

[cavemanit]

So what are some cool gadgets you've seen for the S4?

Here is my list:

Pico Projectors
Cool Gadget - Samsung Galaxy S3 and S4 with the P2 Jr. Pico Projector Review - YouTube

Gamepad:
http://cdni.wired.co.uk/620x413/g_j/gamepad.jpg

S Band
S band - Wikipedia, the free encyclopedia