I don't believe I'm quite at the level to design a DEF CON challenge badge, but maybe I can design an add-on for it.
There is a 'standard' for add-ons for badges, called SAO (someone let me know if there's a better link for the latest standard...).
So I figured it'd be good to design one, that you can make/solder up yourself that may be able to do something, or at least, light up.
I'm interested in your inputs for design, functionality, and creation ideas to get this started.
And I should probably choose which software to design it up in... then maybe we can give some away for you to attach to the next conference badge you get.