Just on a year ago now (almost a birthday!) I posted about the birthday paradox, with a review of general results and then some remarks on erroneous conclusions from DNA matching. In the post there is a subheading called Quadratic Football, referring to the facts that the median of the birthday paradox distribution is 23, the same as the number of players on pitch for a football match (two teams of 11 plus the referee), and this number is surprisingly small due to the quadratic (growing as the square) number of possible birthday matches.
I recently uploaded Methods for studying coincidences to Scribd and found an auto-linked document that presents a small study of birthday coincidences in actual British football fixtures. The conclusion – good agreement between theory and practice. This short paper is well-worth a read.