I like playing blackjack, I might go to a casino one day and try to win a lot of money.
I've played blackjack before.  It is also known as twenty-one. All the players compete against the dealer. 
How long has it been around for?
Good question.  I have no idea. But there are different ways of playing it around the world. In the U.S. the dealer is dealt two cards.  One up and one down. 
What are some other ways of playing it?
Community card poker
Community card poker refers to any game of poker that uses community cards (also called "shared cards" or "window cards"), which are cards dealt face up in the center of the table and shared by all players. In these games, each player is dealt privately an incomplete hand ("hole cards"), which are then combined with the community cards to make a complete hand. The set of community cards is called the "board", and may be dealt in a
Blackjack
Blackjack is the American variant of a globally popular banking game known as Twenty-One, whose relatives include Pontoon and Vingt-et-Un. It is a comparing card game between one or more players and a dealer, where each player in turn competes against the dealer. Players do not compete against each other. It is played with one or more decks of 52 cards, and is the most widely played casino banking game in the world. The objective of the game is to beat the dealer in one