I thought it'd be fun to bring up a story I have from a LARP I as once in at my previous college [and hoping to resurrect where I go now]:
One game, my friend had set up the building we used so the players at one point would hit a trap, fall into a pit, and trip a love potion. At this point, the rules were such where role played effect was attraction to the first thing you saw. One fellow player took this a wee bit too literally, and before long we saw him role playing humping each door in the building we were playing in...." DOOR! *pound* *pound* *pound* OW! MY BALLS!" We were all in stitches - we had to call cut just to regain our composure - SEVERAL TIMES.
The best part? The rule was changed so the aforementioned potion's effect was affection towards the first PERSON you saw... even then I still figures out how to achieve the same results. Have player character trigger a love potion - first person he/she saw [amended rule] in effect - then make said player character hallucinate so a door looked like the particular person to said character. I was a very evil GM when I came on board, if you couldn't already guess.
THAT'S JUST ONE of many stories I have - there are loads more.