I once boiled water with the heat of my hand!
It was in a specially prepared test tube. I admit I had a little bit of
help from a wet cloth at the top, but that was all. The trick was in the
preparation. I got it boiling slightly over a fire and then in a quick
(dangerous) movement removed it from the fire and plugged it with a rubber
stopper. It boiled by itself for a while until it cooled down. Then with
just a little temperature difference, it would boil again.
It also would make scary noises if I shook it, like it was being
hit with a hammer.