I was in the 3rd grade and I had a couple friends on the other side of the class who were making fun of me for some reason, for the ultimate "screw you jerk" statement I decided to stand up and walk over there and do a nice job of crop dusting the isle where they were sitting. My plan was to just lay a ring of stink around their desks, low and behold I was super potent that day and the cloud of foul gas managed to disperse to the rest of the class and I had 20-30 students all mad at me including the teacher.
I still laugh my ass off to this day thinking about it, it was so bad that the teacher made me go sit outside for like 1/2 an hour so I could "vent" away from the confines of the class room. It was so funny because she was an asian lady who had a fairly thick accent and you could here her saw "arrrhhhh,(awww) you weak(reak), you go outwide(outside)now."
That was done on purpose though and definitely wasn't an accident.
I remember accidentally ripping two air biscuits during my highschool years, in each case it was a class room environment where you were quite aware of the fact that you were trying NOT to release any toxic fumes. In one situation one of my friends made me laugh really hard at just the wrong moment and I just happened to "let go" when I forgot that I was making an effort not to cut the cheese.
The other instance was out at a drinking fountain on the football field, some girls were taking a helluva long time hogging the water fountain so I thought I'd go up to the side of it and shake it really good while they were drinking from it. To assure that I made the thing shake really well I spread out my feet to get a good base for a nice stable platform to rock back and forth from, unfortunately the level of concentration needed to succesfully shake the fountain was so great that being able to maintain my focus and shake the fountain was no longer possible. I managed to rip a pretty god one right there on the spot, interestingly enough I think that the air biscuit was a better motivator than my originally planned shaking of the water fountain. Go figure.
My dad is a high school teacher and about 2 years back he made mention of this damned kid that he had in his class who would constantly rip farts in his class. After about 2 weeks of this my dad shipped the kid down to the dean's office on a refferal, it's gotta be too funny for the class to sit there and watch the kid get sent out with a refferal that recommends that he heavily medicate himself on "Bean-O" or that he go out and find an appropriate sized cork.