Shanghai involves five dice & a cup. You put the dice under the cup, shake it several times on the table to mix up the dice, then, without showing your opponents, you take a peek at your dice.
The first person tries to guess how many of a certain number are on the table. For example, if I have the above combination under my cup, & there are three people playing, I might claim that there are in total four 2's on the table. The next person has three choices. (1) They can up the ante on 2's, claiming that there are maybe five 2's on the table. (2) Or, if they don't like talking about 2's, they can choose a higher number to speculate on, saying something like "There are three 3's". (3) Or they can just call the claim & everyone has to show their dice. If the last claim is right, the caller has to drink. If it's wrong, the person who made the claim has to drink.
It's a pretty simple game, but it's hugely popular here. Bars often keep the cups & dice on hand for patrons. If you go out to a bar in Shanghai, you'll most likely hear the clack-a-clack sound of the dice game.