Is there such a signalling device as this?

I’m looking for a buzzer that would go off in response to a radio signal – a sort of wireless doorbell.
I spend a lot of time on the basement computer, which is sufficiently isolated that, with a game or movie on, I can’t hear people calling for me. This occasionally results in missed dinners, missed guests, and much irritation on all sides.
I was thinking of possible solutions today, and came up with an idea for the above buzzer. While I think I would have great fun learning how to make such a thing from Radio Shack parts, it would be quicker and probably more effective to buy an existing product that did the same thing.

Imagine a device rather like a nightlight, only the switch would be activated by a receiver and instead of light, you would get sound; the whole unit would plug into a power outlet. The transmitter would be in another unit, stuck in a different outlet, and would have a manual switch.