Yes, I have dabbled in such things. Actually, right now I am switching the power to a camera on and off by toggling a handshaking line on a serial port that switches a relay (indirectly using a transistor, of course). This will eventually be ported to the NSLU2 (
http://www.nslu2-linux.org) where I will control the relay using a GPIO pin that was originally used for driving an LED.
In the past I have done other things as well, most of them using the serial port, however I have dabbled in parallel port stuff as well.
As far as your strobe light, it should not be hard, as long as there is some way to control when it 'strobes.' I do not know much about strobe lights, but there should be some way to trigger it.
Anyway, that is my $.02, take it how you want.
-Ted