Arbitrage betting is a strategy in sports gambling where you place bets on all possible outcomes of an event at different sportsbooks that offer varying odds. The idea is to exploit the discrepancies in odds to guarantee a profit regardless of the event's outcome. For example, if one sportsbook offers higher odds for the 'under' on a game and another offers better odds for the 'over', you can bet on both and secure a win. This is possible because there are many sportsbooks with different lines, and sometimes they make mistakes or offer different odds that can be used to your advantage.