Hipster alert. This year's Halloween Costume: a fully-functional Instagram camera! Images taken with the front mounted camera are instantly transmitted to the back panel onto a mounted iPad.
A quick rundown on the setup. I used a Nikon D800 with an Eye-fi SD card combined with a portable wifi router. Note that in most cases, the portable router isn't necessary as the Eye-fi card is equipped with a direct transfer mode allowing you to transfer straight to your device. Unfortunately because the D800 isn't fully compatible with this mode, I have to use the router.
At a party last weekend. Worked out flawlessly!
UPDATE: Thanks so much for all your comments! Also a big thanks to the guys at PetaPixel for running a story on it. I gave them some more details on how I put the costume together so please check them out here if interested.
UPDATE 2 : For Canadian viewers: Discovery Channel's Daily Planet program ran a video segment on the costume. Check it out here: http://watch.discoverychannel.ca/#clip847916