Using nothing but an ordinary matchbook, the tap, and a lighter, you can make your fingers smoke.
It may not be safe...
Be sure to wash your fingers after. The residue is toxic. The residue created in this process contains Urea fomaldahyde, which is a known carcinogen, and Red phosphorus, which can be potentially harmful. The smoke you see is the red phosphorus vapourising caused by the heat produced through friction. However, it should be pointed out that red phosphorus can revert to white phoshorus under frictional heat. White phosphorus is highly toxic!
Formaldahyde is used for embalming. It changes cell structure permanently. It's ok for dead people but not for the living. Cell deformity can cause cancer. If you have to try this experiment please wear latex gloves.
The red phosphorus on the side of the matchbox evaporates because of the heat, and when the vapors condensate on the cold tap, they convert into white phosphorus, which is indeed highly toxic, especially if you rub it into your skin. :P
They sell this substance in large tubes at magic stores. I've used it for various fun throughout the years. And yes it smells like all hell.. Great impromptu source and video, just easier to buy it.