We had a frat bro who loved to entertain the "crowds" by lighting his methane.
During one command performance, he was sans undies, and in an effort to produce said gas, instead hit a small "gusher" and sheet-sharted. Hilarity ensued, tear ducts and stomach muscles were strained that day.
When we were kids we had heard jokes about farts being flammable but didn't really realize how that could be possible and didn't really believe it. Then one of my buds asked our 4th grade science teacher about it and he explained methane gas etc. etc. etc.. After hearing that you bet your ass (no pun intended) that we were going to try it out. My best friend Danny went first with like five of us guys circled around to watch. When his butt lit up like the 4th of July we laughed so long and so hard it was painful. We even took it farther and farted into a Coke bottle and quickly covered it up then dropped a match in it and..... FOOMP!