One night, my housemate Daniel Efran and I were sitting around feeling creative. I'm not sure if we were drinking or not, but there were a bunch of empty beer bottles lying around.
Dan recently had been experimenting with a model making material called Mountains in Minutes. This stuff is usually used by model railroaders to make big foam hills. It comes as two syrupy liquids. You mix the two liquids together and after a few seconds the mixture foams up. It expands to many times its original volume, then hardens into a styrofoam like mass.
I'd had the idea that maybe it expanded fast enough to spurt out of a bottle, and if you could get it to spurt up high enough, maybe the spurt would harden in mid-air. (Come to think of it, we must have been drinking.)
Anyway, Dan had plenty of the stuff lying around, so he decided it was worth experimenting upon. To encourage the spurting action, we rescued a bottle cap an put a small hole the middle. After putting some M-in-Min. into the bottle, we capped the bottle and stood back.
In retrospect, it was an awfully good thing we thought (or were reminded, most probably, by Zarf) to put a bunch of old newspaper underneath. Absolutely no spurting of any kind occurred. The foam rose up into the bottle, flowed out the hole in the cap, and down the sides, just like a beer gusher. Unlike your standard beer gusher, the foam hardened into a solid mass, and became an objet d'art.