The five lecture series was entitled "The Num8er My5teries" and discussed such things as why cicadas only emerge from their holes every 17 years and sunflowers have 89 petals, the reason bees make honeycomb in the shape of a hexagon, the best tactics for surviving on a game show, the German enigma codes and why weather prediction is so hard ... how can you still believe mathematics is boring :-) ?!
The Guardian's education supplement ran a nice interview with du Sautoy a couple of weeks ago.
Update: I found the article du Sautoy wrote for Seed magazine. In it, he explains the connection between the number 42, mentioned in the Hitchiker's Guide to the Galaxy, quantum mechanics and prime numbers.