Every round, each player receives a stack of 5+ hidden cards. Simultaneously, they sort them according to one or more public criteria (simplest example: higher number on top). To achieve this, a player may only use one hand, and may only hold one card in hand at any time. He may use any number of temporary stacks on the table, but the cards on table must be kept face-down all the time.
The first players who manage to accurately order their stack gain a chip. This takes them closer to victory, since the goal is to collect six chips. But for each chip you already have, you receive one more card to sort, so players behind have a good chance to catch up.