maybe a low-voltage sound or liquid level detector circuit that could turn on or drive an amp that feeds into some white LEDs to supplement the existing lighting rather than interface with the AC.
I'm thinking a op amp as a level detector to go to full output, that would in turn activate a 555 timer circuit configured as an oscillator to drive the LEDs. I haven't done elctronics for fun in a long time - just safety these days. There's a lot of time between now and April 1st...
