Part of what makes sport in general so great is the fact that you never know what's going to happen. You know what SHOULD happen, but it's the unpredictability which makes everything that much more exciting. There's nothing better than a huge shock result to get people talking - and there have been some absolute crackers over the years...

1. Cassius Clay v Sonny Liston: The brash 22-year-old upstart shouldn't have stood a chance against the heavyweight champion of the world, but Clay - who changed his name to Muhammad Ali the day after the pair's first fight in 1964 - did the unthinkable and took the title from his bigger, more experienced opponent. It was a result that sent shockwaves through the world of boxing and turned Clay into the biggest sports star on the planet.

2. NY Giants v New England Patriots: The Patriots had reached the final of Superbowl XLII with an unblemished record and were hot favourites to finish the season with a 19th straight victory, but they didn't count on one of the biggest upsets in the history of the game. Eli Manning's pass to Plaxico Burress with just over 30 seconds left on the clock created the winning score as the Giants ran out unlikely 17-14 winners.

3. Foinavon wins the Grand National: Beginning the race as a rank outsider at odds of 100/1, even the horse's owner didn't bother making the trip to Aintree to watch! It was all going to form until the fence just before Canal Turn. One horse fell, setting in motion a domino effect that left carnage as all the leaders were thrown from their horses. Foinavon was so far back at this point that jockey John Buckingham had time to steer around the mess and take the lead. He held on for the most unlikely victory in the history of horse racing. In his honour, the fence where the leaders all fell was named after Foinavon.

4. Wimbledon v Liverpool: The final of the FA Cup in 1988 was supposed to be a walkover for Liverpool, the crowning glory in a season which had seen them lift the First Division trophy a couple of weeks earlier. But the Crazy Gang, who had been playing Fourth Division just five years previously, ripped up the form book as Lawrie Sanchez popped up to head home an unlikely winner for the underdogs. The game will also forever be remembered for Dave Beasant's penalty stop from John Aldridge - the first time a spot-kick had ever been saved in an FA Cup final.

5. USA v USSR ice hockey: The 1980 Olympics saw a team of amateur and collegiate players from the US go up against the highly-favoured, well-organised team of what were to all intents and purposes professional players from the Soviet Union. The Americans weren't given a cat in hell's chance of winning, but surprised everyone - themselves included - by running out 4-3 victors in what became known as the ''Miracle on ice''. The US team went on to win gold while their Cold War foes had to settle for silver.