The All England Club are running a daily competition to win tickets to the Wimbledon Mens and Womens Final plus other games.
They release a new clue every week which you have to use to find the hidden link on their page for the competition entry. Todays link is on the "Visit All Year Round" --> "Guided Tours" page
EDIT: Sorry its a weekly comp not daily!
UPDATE: New chance to win today, link to tickets are on this page, answer is 1555 http://www.wimbledon.com/visiting/museum