Igniting a propane bomb with my P-Chem professor. I was in a volunteer group of chemistry students that gave chem demonstrations to area middle and high schools, science day, chemistry day, campus family day, etc. We were staying late in the chemistry department practicing demos for science day later that week. It was about 11 p.m. and a few students and I wanted to mix propane and oxygen in the stoichiometric ratio in an empty 2 kg plastic reagent bottle. We jerry-rigged a fuse in the cap. Our advisor was a p-chem professor in the department. He found out what we were doing, and to our surprise, suggested we set it off outside between the science building and the fine arts building. Little did we realize that that area was essentially a bowl (the ground was bowl shaped, and the two buildings were concave, both interiors facing each other at about 30 yards apart. Echos galore.
We lit the fuse and all of us ran (prof, too) around the corner of the building. The BOOM was probably heard on the other side of the campus. I'm surprised we didn't shatter every window in both faces of the buildings! My p-chem professor said, "Umm, maybe we should pack up and get outta here before campus security shows up..."
Good times, good times.