Well for contact explosive, you could always just make some nitro from soap. I mean, I see that shit in movies all the time, so it's gotta have some amount of truth to it. Also, I forget what it was called, but back in high school my class convinced the chemistry teacher to do an experiment that created contact explosives. He ended up making about 10 times as much as the stable-when-solid amount, freaked out, then spent like five hours at the fume hood just letting little bits of it solidify, then tapping it with a meter stick. Good times.