Gambling games, as the name suggests, are games of speculation, for the outcome depends solely on chance, without any reliance on skills, training, knowledge, etc. This definition excludes online games as games of skill though the two are often confused. The more common types of games are the ones associated with casinos, where a person bets his money either for winning a jackpot, to buy a ticket, etc., or to pay for gambling fun (to win for consumption or for gambling purposes).
Poker is one of the most popular games. It involves a number of betting rounds (which can go all over the game and back to the starting round, at which point the bets are made), each of which has a set limit (no matter the number of players playing). The best possible outcome of each betting round is revealed at the end of it; the player who wins the highest score gets to keep whatever he won, and the other players lose what they rolled.