"Twenty One" is a popular card game often played in casinos, also known as Blackjack. The objective is to beat the dealer by having a hand value closer to 21 without exceeding it. Players are dealt two cards, and they can choose to hit (take another card) or stand (keep their current hand). The game uses a standard deck of 52 cards, where numbered cards are worth their face value, face cards (Kings, Queens, Jacks) are worth 10, and Aces can be worth either 1 or 11. The game combines elements of chance and strategy, making it a favorite among gamblers.