It's becoming a bit of a tradition, now, to do mean things to peeps at the Hackerbot Labs around easter time. Last year, we electrocuted some peeps in a vacuum; this year, we opted for freezing them in liquid nitrogen and then shooting them with a pellet gun, as seen here.
Many thanks to Xander and Phil for their help in setting up the circuit (photo) for doing the triggering (on an Arduino), and to 3ric for supplying the LN2 and a fair bit of the inspiration. Thanks also to Bre for sending his high-speed photography rig our way, though alas it did not arrive in time to use it (which means extra special thanks to Xander and Phil for getting something else together in time), and to Lisa for doing a bunch of the clean-up, and to everyone else who helped out in one way or another.
The flash used was my newly purchased Vivitar 285HV, at 1/16th power, camera right sitting on a box about 18" away in wide angle mode with the diffuser in place, triggered as documented above (more details and more pictures of the setup (including me using "chopsticks" to place a peep) are in Xander's stream).