Ah, I hear you there. I think I have the weirdest sense of humor in my class. During Math I laugh about mathematical formulas sometimes. Recently it was the sin (sine), cos (cosine), and tan (tangent) ordeal. I pictured it as an allegory to life and as my class looked at me I started to giggle with my head on the desk.
In Science I started laughing when we were learning about different cloud formations. That was the class when we learned about lenticular clouds and were shown a picture of them. No wonder so many people think they spot UFO's, lenticular clouds resemble them exactly.
And in History I oddly find it funny how many rebellions have failed. Call me odd, whatever, but I just started laughing hysterically when we learned about the great slave rebellion of the Ancient World in which 7,000 people were crucified.
(Either 7,000 or 70,000, can't remember.)