These are the speaker badges I threw together for the speakers of the newly formed Kansas City Open Hardware User Group's (http://kcohg.org/) inaugural meetup hosted by CCCKC and the Kauffman Foundation. I've used a variant of this design before and wanted to share it so figured it would be a good idea to release it for the event, being in the spirit of open source hardware and all.
These are basically just 3mm acrylic edge lit by a 3mm ultra-bright LED and a battery (CR2032, thinner batteries like the 2025 might not work or be as reliable). The LED and battery combo is held in place by a couple of 0.06" thick plastic covers and snap-lock nylon rivets:
The whole thing assembles in seconds and you can even put a little slip of card stock between one of the legs of the LED and the battery and let it hang out from under the cover so you can pull it when you need to use it. They last about 2-3 days at reasonable brightness so they're perfect for most cons.
The design itself is just something I quickly threw together with the OSHW logo (oshwlogo.com).