In a blackjack tournament, all participants receive a certain number of tournament chips and then have a certain time period or number of hands to run up their balances as much as possible. Payouts are based on final finishing position on the tournament leaderboard. Some of these blackjack tourneys are free to enter, but others require the payment of a buyin and possibly rebuys.
Among the online blackjack casinos known for numerous blackjack tournaments are BetOnline and Everygame.