My friends and I once pissed in four beer bottles, put the lids back on them, and let them chill in the bottom drawer of the fridge for a few days, knowing that someone would eventually find them when we ran out of beer and think it they'd found a forgotten beer stash.
Well that day came, and our expectations were overly exceed. The kid in the video found the bottles, so we told him he should chug them all...and he did....all four of them. After the third bottle, my friends and I were so amazed that he'd gotten that far without realizing it was piss, that I emptied the fourth bottle and refilled it with fresh piss before he came back into the house. About a minute later, he was finishing his fourth and final bottle of piss. He didn't find out that it was piss until he saw the video on youtube about two weeks later.
This is the video of the fourth bottle, full of my warm piss. I'm the jackass telling him to finish it, and my bottle was full of water.
It was one of the funniest experiences of my life watching him down each bottle. We were blatantly using the word 'piss' in every sentence, but he was too thick to catch it.
Edit: we're working on compiling all of the cell phone videos including the first three bottles so we can make a highlight reel of him downing all 48 ounces of piss.