Some v0 and v1 badges fail when plugged in to USB, the MCU develops a short and destroys itself!
If you have a v0 or v1 badge install a 10uF cap between pins 4 and 8 (VSS and VREGIN) on the BREAKOUT1 header.
Instructions for building firmware and flashing your badge is in [laser-tag software/README](laser-tag software/README).
Join #ahabadges on Freenode.