Gambling is the betting of money or anything of value to an event with an uncertain outcome. The two main types of gambling are chance-based and skill-based. Chance-based gambling includes the lottery, roulette, and gaming machines. The result of these games is random and can't be influenced by the players. On the other hand, skill-based gambling, such as playing poker and blackjack, is controlled by the player's skills. However, the winning odds are not the same for all players, and having the skills does not guarantee a sure win.