http://wiredinsider.com/meettheinsiders/
Just enter something you have already made. I would enter, but I am not 18...
Check out week 7:
"WEEK 7: MAY 30-JUNE 5
Maker Challenge: Do it Yourself! Make something on your own and Tweet us a picture or video of your creation.
@Adafruit’s Limor Fried and @Etsy will be our guest judges."
prize: Week 7 Maker: one (1) Adafruit Ice Tube Clock (ARV $85); one (1) Dead Zebra DIY Android (ARV $7); one (1) Gessato Alice Co. Toolbox (ARV $47); Makerbot Thing-o-Matic 3D Printer (ARV $1,299); one (1) Thames & Kosmos Fuel Cell 10 Car and Experiment Kit (ARV $150). The approximate retail value of the Maker prize package is $1,587
