Today (at least in countries which write dates M-D-Y) it's Pi Day, so named because the date is 3.14.15, the first five digits of Pi.  WotC's Twitter feed posted a fun little picture which I figured some folks might find amusing.  Spot the Pi!  As WotC said, "Wait, today was something special? We were just sitting around playing D&D and eating pizza."  For myself, today is 14.3 day, which is not quite the same! (Though 22/7 is an acceptable alternative in July).