RE: Smoking Building
Tankhobby sells a detector for $16 that can trigger a relay when hit by IR (and hence light a model rocket ignitor fuse or actuate a servo to "blow" something up). It's a little non-selective (it can be triggered by an appropriate tv remote) but would work in a pinch. A slightly more advanced circuit could use a PIC microcontroller to detect the actual Tamiya battle signal and count hits before triggering. Would make it easier to have a reinforced bunker that took a good number of hits rather than a lucky snipe shot to destroy it...
D.