The two-year countdown to the London 2012 Games begins today with a game of table tennis.
Triple jump world record holder Jonathan Edwards faces 19-year-old champion Darius Knight in the first of 900 sporting, cultural or artistic events on offer in the London 2012 Open Weekend.
Now in its third year, organisers of the Open Weekend - from 23 to 25 July - are urging the public to challenge themselves and try to do something new or take their hobbies to the next level.
There are table tennis challenges in London, building your own boat in Wales and bicycle ballet in Manchester.
2012 Open Weekend at Rich Mix
Free workshops, sport taster sessions and stage performance start from 12pm and BBC London 94.9 will broadcast a live sports show hosted by Eddie Nestor and Phil Parry.
Rich Mix is based at 35 - 47 Bethnal Green Road, London E1 6LA
Participants can help bring a giant kettle to boil via music in Milton Keynes, run a leg in a 3k relay race in Walsall, making their own stone sundial in Souter and try a talent contest in Norfolk.
London 2012 chair Lord Coe said the weekend is the chance for thousands of people, who perhaps are not natural sports lovers, to join in with the London 2012 Games.
More than a million people have taken part in previous events.
He said: "Open Weekend will lead the nation into the two year countdown to the start of the London 2012 Games with new personal bests being set right across the UK."
Edwards and Knight are taking part in Passport to Pingland - a pan-London ping pong project funded by Sport England and delivered in partnership with the English Table Tennis Association.
By completing a table tennis challenge they earn a stamp in a special passport.
They can earn a top quality bat by getting three stamps but they have to be collected by doing challenges at different venues.
Passports can be collected at participating sites.
Locations across London include Hoxton Square, Geffrye Museum, Gillette Square, Victoria Embankment Gardens, Soho Square, the Natural History Museum, Brunswick Shopping Centre, the British Library Courtyard, St Pancras International, Bermondsey Square, the Tate Modern and the O2.
Open Weekend on BBC London
As part of London 2012 Open Weekend, BBC London has joined forces with the Rich Mix Cultural Foundation in Bethnal to put on a family festival ahead of the Olympic two year countdown.
From 12pm-6pm enjoy sport taster sessions and watch the BBC London's sport team in action as they present their show live from Rich Mix.
At 2pm you can take part in our live Q&A session where you'll have the opportunity to put your Olympic related questions to the people that make the decisions. You can email questions in advance to:
From 8pm join BBC London's DJ for her World music in London programme with performances from Carnaval del Pueblo live on stage.