This will almost positively absolutely gross you out but when I was travelling with some friends to Canberra they decided to play a trick on me.
At diners along the highway you can get hotdogs, I was tired from riding behing the car on my motorbike, nothing too flash, just a Honda CB250S or Nighthawk, she's my baby

(see link for a pic)
http://www.250ccbikes.com/images/upl...0617173448.jpg
Anyway, so I asked them to get me a hotdog and a cuppa tea for dinner and since on of the girls with us was on her erm... "cycle" she or one of the guys decided to put a used sanitary device in my food along with the sausage in the dog.

: puke :
When they all came back the guys were sniggering... I got paranoid and woke up a bit more when she handed me the food, just as I was about to take a bite the girl looked like she was about to crack up, I said, "You look hungry, do you want a bite?" She went pale and declined, I got sussed out and checked the food. I was thinking chili sauce or something right... Wrong. I asked them whose idea this was... Turns out it was one of the guys, needless to say I beat the LIVING SH!+ out of him but it was close. Too close.
All I can say now is thank god for paranoia!