More than 21,000 tickets have already been sold for Leicester Tigers' first-ever visit to the Ricoh Arena to face Wasps next month.The fixture comes in Round 20 of the Aviva Premiership Rugby season, with precious points up for grabs in the race for semi-final places and European qualification.   The Tigers allocation of tickets was snapped up very quickly from the Welford Road ticket office and tickets for ‘The Stinger’ fixture on Saturday, May 9 are now on general sale from Wasps.   ‘The Stinger’ matchday includes live music and children's activity area, while the Fan Zone in the Jaguar Exhibition Hall will hold bars and food outlets. Before kick-off the winner of 'Wasps Unplugged' – a competition run to discover local music talent – will provide the warm-up to the match.  Wasps also plan to distribute 15,000 Ashley Johnson wigs for fans in honour of their favourite player and to raise funds for the Wasps Academy's charity partner, the Brain Tumour Charity.  Tickets can be purchased at the Ricoh Arena, online at www.wasps.co.uk, phone the Wasps ticket line on 0844 847 1867 or via Ticketmaster at www.ticketmaster.co.uk/wasps