Bestival
A similar thing happened to me at Bestival this year - On the saturday a guy we were camping next to had got in a right old state and, for reasons known only to himself took a piss IN the tent I was sharing with three of my friends.

This simply could not be left; deadly retaliation was required. You can't just let tent pissers get away scot free. So when we came back to the camp on the sunday night, we were delighted to find the bloke already in his tent and happily passed out. It was time to strike.

My friend Sam, one of the other tent occupants, somehow procured a cup. Talented man, our Sam. Useful to have around. He filled it all the way to the top with steaming, aromatic, thunder yellow piss and, for good measure, took it somewhere a little less exposed, pulled down his cacks, and deposited into it the most perfectly formed nugget of faecal matter I've ever had the good fortune to witness. It's buoyancy was such that it just hung suspended in the wee wee, solid of consistency and horrifying of smell.

The deadly cocktail was placed outside our poor target's tent, in such a way that all but the most nimble and gymnastic person would invariably knock it over when they emerged. Philbert (the tormntee) was neither of those things and would also be suffering from a decent-sized hangover in the morning, so our plan was assured.

We woke up before him in the morning and to our delight the turd had marinated - a rich shitty pissy paste now filled the cup, its odour permeating the neighbourhood insidiously. High fives were exchanged with Sam. Truly, it was his masterpiece. Philbert, though, was less impressed when he knocked over the cup and its gruesome juice spilled forth copiously over everthing.

That showed him.
(WarneMarsh My priority for frivolity begets quality jollity, Wed 20 Jan 2010, 15:22, Reply)