I convinced my AP Chem teacher to make it for me in HS, and she told me that back when she was a grad student she was in charge of running a lab of undergrads. One April fools day she made up a diluted batch, and while it was still liquid painted it onto the entrance to the classroom, and a tiny bit on several random chairs. Said the POPPOPBANGBANG it made when the first student walked in was only slightly less priceless then when they sat down on said chairs...
Awesome stuff - but its not exactly safe - I remember very vividly in my class she made the TINIEST batch of it, and made some serious noise when it dried. Wouldnt want to SIT on it, thats for sure.
ETA I think I read somewhere that another hilarious application was painting/injecting it into doorhandles/locks.