yeah, it's possibe. but you might need a pretty advanced circuit to succed.. i can't tell you how to wire it, but i know it's possible.
buy a really cheap sound system and whack up the bass and watch the power led dim and react to the bass .
Either get one of the modules for CCFLs ment for that purpose or make it yourself, not that hard. Do you want to have a connnection to your sound source, or just a pickup mic? Just hook up the mic/line source through a low gain transistor, that through a pot as a voltage devider, than through a darlington to make the light switch. I'll post a schematic, but cpemma will probley come up with something better EDIT: linky http://www.frozencpu.com/cgi-bin/frozencpu/lit-37.html and a quick schematic. In that basically what I'm doing is taking the output from a mic (hack up one of the cheap boom mics) amplifying it a little bit with a transistor, using the pot, to adjust the level, the cap smooths it out, the zener keeps it off when the voltage is below 5.1V, the final triansistor is missing a base resistor, don't forget that when you make it, dont want to burn it out. I think the 2222 can supply 1A, if you wan't more, hook up a power transistor to the "to load" line with a small resistor. If you were using a line out from a soundcard, you would have to put a resistor on the first transistor also.
This circuit will cause the output to turn on with any sound, not just bass. If you wanted the light to flash with just bass you'll need to add a filter, which could be something as simple as a single inductor.
I'd be tempted to use an active filter built round a cheap opamp, just copy the bass channel of a sound->light circuit.
