I've recently mastered (c.f. "learned not to soak myself") carrying three full 200ml drinking cups in each hand without getting my fingers below the waterline. I'm working on four. Why did I do this? I have no idea. I was bored, and most of the drinks at the vending machine are free. My time is clearly not very precious. It got a few laughs out of my work colleagues, but unless I obtain an audience of cup-fanciers, on its own it has limited mileage as a performance piece.
Then I got thinking. Performer comes along with six cups of water, three in each hand. He "clumsily" waves them around, giving the impression he's about to spill water everywhere, talking about how this entertainment lark is thirsty work, and how easy it is to get dehydrated. How most people don't get enough fluids, and not drinking enough affects your concentration.
He then downs each cup of water one after the other in rapid succession. This is over two pints of water, drunk in under a minute. He announces that, having drunk so much, he's now super-hydrated and capable of amazing feats of concentration. With the cups, he does a cup-stacking routine, simultaneously asking someone to call out two four-digit numbers. He calls out a number which could plausibly be the product of these two numbers.
He then brings the cup-stacking to a close, lining up all six cups face down in a row in front of him and asks a spectator to pick any one of them and concentrate on it. He picks up the selected cup, points out the curious connection between concentration and water, and proceeds to demonstrate in the most spectacular way possible (throwing the liquid through the air, pouring it over himself...whatever he can get away with in the setting) that the cup is actually full. All that concentration, he comments, has to go somewhere.
Speaking of which, he says, having just drunk all that concentration, he really needs to excuse himself. He thanks them for being a gracious audience, and vanishes off into the night, or possibly the Gents.