It's a simple game, really. The pickpocket places something of great value to you (jewelry, currency wad, ident implant [don't ask how he picked THAT off your person]) under one of the shells, along with an exploding bean. He gives you a mallet, then he starts shuffling. You guess by banging on shells. The goal is to pick the two shells your valuables are NOT inside by smashing them flat. If you're wrong, and your valuables were sturdy, you're still screwed because the bean explodes hotly on impact. Oh, and when you took your hands out of your pockets to use the mallet, a member of the audience behind you (the pickpocket's partner) will rob you blind.
For those who think this is a stupid game that they would never consider playing, it's a great alternative to Turbingian 10-chamber pistol-roulette.
Send the rest of the troops home, too.