Calling all sports fans and calling all maths fans. Tomorrow at 1pm John D. Barrow, cosmologist, best-selling author and director of the Millennium Mathematics Project (the home of Plus), will be starting a lecture series on maths and sport at Gresham College in London. The first lecture is entitled How fast can Usain Bolt run? and there'll be five more lectures until the end of March, looking at Olympic sports from rowing to jumping. All lectures are free. Visit the Gresham College website for more information. If you can't make it to the talk, a video will be posted on the Gresham website a few days after it's happened.