3/14 may be "Pi Day" for some, but it is also recognised by the Commander Keen fandom as "Commander Keen Day", due to 314 being our hero's IQ score. Since Keen himself is American, we can get away with using the otherwise irregular M/D notation for the date to get 3/14, whereas the number "pi" (3.14, to 2 decimal places), however, has little, if any, Americentric significance. It should be noted that Commander Keen is a fan of many sweet foodstuffs, often stuffing his face with candy and cereal at every step of his adventures, so whether you observe Keen Day or Pi Day or both, eating pies in honour of the date 3/14 is still an appropriate tradition.