One of the teaser formulae that Ramanujan sent from Madras/Chennai to Professor Hardy in Cambridge was another approximation for Pi
Because, Watson, you are rather less bright than the silver cap of my pipe <puff> . . . <puff>.
While we're on the subject of Pi, why not print out the first million digits and have a look at them on an airfield? And now for something completely different: Mayday's talk by Grime about Ramanujan's Summation.
Jeremy and Dev talk about the film and other matters on WBUR: listen up it's sort of heart-warming.