As the Wimbledon 2011 Championships hove into view, memories will be reawakened of the match of epic proportions that took place last year between the American John Isner and the Frenchman Nicolas Mahut. So just how freaky was their titanic fifth set and what odds might a bookmaker offer for a repeat?

David Spiegelhalter explains that waiting for an infinite number of monkeys to produce the complete works of Shakespeare is not just a probabilistic certainty, it also gives us an insight into how long we can expect to wait for a rare event to happen.