While this year's Sevens might have been and gone, you won't be able to avoid thinking about rugby if you go anywhere near the HSBC building over the next two weeks. A giant game ball has been placed on the ground floor of the bank's Central headquarters. It is filled with ping pong balls. The installation is for a contest organised by the bank - and the Post is lending a hand. As sponsor of the British and Irish Lions' tour to South Africa this summer, HSBC is inviting fans to guess the exact number of ping pong balls. The three closest or exact responses will win a trip for two to South Africa, including accommodation and transport, to see the test match in Durban on June 20.