Ah! We had that at Summer Camp! ^_^
Summer Camp was made up of companies, but there was one Platoon separated from the rest, the Leadership Platoon. Dude, they were the black hats. Don't disrespect them, do whatever they say, yes sir and no ma'am, sometimes we were even scared to look at them, which was weird since they weren't ever mean. Just... Their hats, their position in the Platoon, gave them power and respect. LOTS of respect.
Anyway, during breakfast, lunch, and dinner, whatever we didn't drink (and I mean all the companies) we poured into this huge drum that sat next to the trash. No one knew what it was for, but it was filled with everything. Milk, bug juice, food, trash, a nasty mix.
Well, my boyfriend was in Leadership Platoon a couple years ago - before he graduated - and it turns out, on the last day, the LP got to eat dinner where the officers and cadre eat, which was a real fancy room next to the regular mess hall. No one ever saw in, we only knew we had to salute the officers and cadre going in and out.
So this last meal for the LP was in there, and they had a "game" where squads would challenge each other with trivia. Someone'd raise their cup, challenge a team, and ask a question. If the challenge-ees got the question wrong, they got to drink from the Grog Pot. If the question was answered correctly, the challengers had to drink from the Pot. Ugh...