Random, yes. Interesting, probably not.
Keep in mind that this is at a school where cameras point everywhere, a strict dress code is enforced, and teachers are all too happy to assign detention. Kids being weird are quite rare.
9th grade: Two other guys and I would burst into Bohemian Rhapsody in quiet periods in class and in hallways. The bio teacher even reported us to the choir director once, as there was a need for male singers at the time. The novelty wore off after a while though.
Whenever a car full of people passes somebody that all passengers know on the sidewalk, it is customary to honk and wave in the opposite direction.
Physics gets extra-special permission to be weird. That class has a lot of outdoor labs and labs that involve exploring/observing things in the school building, so being weird is tolerated.
One time we were allowed to take sound readings in different rooms to measure how well a room absorbed sound. A couple of us would waltz into a classroom, nothing said, take a reading, and leave. A few teachers asked, "What are those things?" to which we replied, "Geiger counters. Carry on," followed by some whispered remarks like, "Hmm... hey $name, is it supposed to read that high?" "Uhh... no. We better tell [physics teacher] about that one, quick," after which we left hurriedly. This was quite fun to do to freshmen that didn't know any better.
Another: we got to do some experiments with prisms, polarized filters, lenses, and the like outside. To get outside, we need to walk past half of the classrooms. Classes that keep their doors open. Physics easily being the most eccentric group of them all, we each taped these optical instruments to pairs of chemistry goggles and proceeded to stagger our way across the length of the school. We got some strange looks, to say the least.