This is an idea i've been toying with for a while, just needed an excuse to get off my backside and do it, I have no excuse really cuz I work in the RC hobby industry.
It would be easy to set up some servo's to turn targets, I considered metal plate targets with piezo elements attached to detect a hit and iluminate a lamp and controlling it all from my Nintendo DS over wifi or maybe use a pair of nRF2401's
incidently for awkward or long range data transfer i've started using these TL-PA211 | AV200 Mini Multi-Streaming Powerline Adapter | TP-Link
allthe benefits of wired ethernet but without trailing wires