When I was in high school, my buddies and I figured out if you put the fuse of a cherry bomb in the cold end of a lit cigarette, it would take about 20 to 30 minutes for the cigarette to smolder down and light the fuse.
One evening we planted about a dozen of them around town, and then sat in my car on the courthouse square listening to them go off. The Chief of Police strolled down and struck up a conversation. He had an idea we were at the bottom of it, but he couldn't figure out how we were doing it.
About the time the last one went off, he said, "Well, it's getting kind of late. I think it's time you boys headed for home".