Metallic sodium is commonly used in synthetic labs as a counterion source in syntheses where you don't want or can't use an alkoxide or other base. We had some in my lab in grad school. It's not some weird, wild chemical that only terrorists or drug makers would use.
We used to have sodium kept stored in mineral oil in high school chemistry class.
The story is told of how one of the teachers supposedly wanted to dispose of some old sodium. He rigged some contraption out on the football field where he would pull on a cord and then a bucket of water would be dumped on the block of sodium.
Apparently, the mushroom cloud could be seen for quite some distance.