Even though the athletics (track and field) events do not officially start until August 3, I heard news that the Olympic cauldron has been moved to a more safer place within the Olympic stadium. Therefore, the organizers can prepare the site for athletic competition.
With 47 different events (and 141 Olympic medals to go for), it is the marquis sport of the Olympic Games. For a preview of the August 3 medal and qualification events, come here.
Link: http://www.london2012.com/athletics/schedule-and-results/day=3-august/all-day.html