A more serious suggestion:
There's a thing going around Yahoo and YouTube about an effective room heater which consists of four tea lights in a baking tray with two inverted flowerpots on top. From the coverage I've seen it does actually work. OK, you won't be sat there in t-shirt and shorts, but it keeps the room warm enough and they reckon that - based on a bag of 100 Ikea tea lights for £1 - it would cost about 8p a day to keep a room warm.
Only thing is, the baking tray and inverted flowerpots are a bit rough and ready. A properly designed unit (possibly sold with a stock of tea lights) might be a seller?