I'm reading the CIA Simple Sabotage Field Guide, and it's altogether an amazing work, but this is my absolute favorite part:
"Anyone can break up a showing of an enemy propaganda film by putting two or three dozen large moths in a paper bag. Take the bag to the movies with you, put it on the floor in an empty section of the theater as you go in and leave it open. The moths will fly out and climb into the projector beam, so that the film will be obscured by fluttering shadows."