Arduino-Powered Remote "Detonator" (Airsoft)

Ok, so I play a lot of airsoft. I'd like to add some more variety to my team games, so I wanted to add a demolition-style game. I already have made a timed "explosive" that sounds a relatively loud speaker when the timer is up...but I'd like to make a remote "detonate-able" Mock C4 that lights up some LEDs and Sounds a speaker...however I'm stumped...How could I do a wireless remote "detonator"? Help please? P.S. I am not a terrorist. Also this device would lack the functionality to detonate actual explosives.

Search for "arduino wireless fob"... http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1249665441