A £40 million programme of key test events will be vital to "challenge" and try out new venues, equipment and staff in time for the Games, London 2012 chief executive Paul Deighton said today.
The year-long schedule starting this month covers 42 events - many set to feature 2012 medal hopefuls - at 26 venues. It is designed to create the kind of issues that could happen during the Games.
Up to 250,000 spectators across all the events will be able to watch what London 2012 is billing as the "world's largest rehearsal" during the testing series, called London Prepares.
There will be 150,000 tickets going on sale to the public, costing from £5 to £35.
Mr Deighton said organisers are trying to be "creative and pragmatic" about the programme because it will not be a mini-Olympics but a chance to put Games staff, volunteers and organisers through their paces.
He said: "The London Prepares series is essentially about putting our plans into practice.
"Although our venues won't be dressed in their Games finery, a number of events will give the public a chance to see some world-class sporting action ahead of next year.
"These events are our opportunity to try out our new venues, test new technology and equipment and walk our extended teams through their roles and responsibilities.
"We have learned a lot from previous Games, which we will put to good use as we challenge ourselves over the next 12 months."
The focus will be the field of play where the sporting action takes place, trying out the technology and also seeing how the staff who will be at the Games will manage.
Mr Deighton is not expecting everything to run smoothly. He said: "We do not expect to get everything right and if we did I would be slightly unhappy.
"We are going to be testing very thoroughly and diligently and learning from mistakes, put them in to our plans so that we can deliver what we need to deliver."
Some of the cost of the rehearsal events will be met by ticket sales and sponsorship, but Mr Deighton stressed he did not see the tests as a commercial brand. "It is all about testing," he said.
Basketball and BMX will be the first competitive sports to be held at the Olympic Park.
The four London 2012 test events this summer that will be ticketed are: mountain biking at Hadleigh Farm in Essex on July 31, beach volleyball at Horse Guards Parade on August 9-14, plus basketball on August 16-21. There is also the BMX test event on August 19-20.
A new platform for the equestrian events at Greenwich Park, new marking lanes at the rowing lake at Eton Dorney in Buckinghamshire, and delivery of 3,000 tonnes of sand for the beach volleyball will be among the wide-ranging things that will be tested.