Put it on top of a speaker, and it will form writhing tendrils.
Useful information gleaned from comments sections: if your little brother puts it in your hair, just add some vegetable oil, and it will slither right off.
Wandering in random YouTube-association land, I found a new use for liquid nitrogen. When I was a kid hanging out with my dad at work, he used to get me out of his hair by giving me some to play with. He produced amusing effects by gargling it (just don't swallow). I wish I'd realized back then what it looked like when you poured it on top of water:
I think the kid was risking asphyxiation when he swam into the thick cloud.
For extra science fun, type in "Is it a good idea to microwave . . . " on YouTube.