The Gold Rush is on again. Novak Djokovic and Andy Murray are joining the search for gold hidden in a total of ten HEAD ATP tennis balls worldwide. In addition, the main winner of the 2013 Golden HEAD Ball promotion will enjoy a trip to London with two tickets for the 2013 Barclays ATP World Tour Finals. Joining the HEAD ‘Gold Rush’ is easy: find a code inside a HEAD ATP Ball can and check it online. Or simply register on http://www.head.com/tennis/goldenheadball/ for a chance to win one of the more than 1,000 attractive prizes.