Betfair is a person-to-person betting exchange. Bet on all sorts of sports and more - even while they are still happening! Line betting is also on offer, allowing you to buy and sell outcomes up to a specific value. This is like spread betting, but the amount that can be won and lost remains static. Also range betting. There is a good help facility.
Sports include american football, basketball, boxing, cricket, darts, golf, greyhound racing, horse racing, ice hockey, motor sports, rugby league, rugby union, snooker, football and tennis as well as financial bets and specials.