Today is Patriots Day here in Massachusetts (it is also observed in Maine). This is a state holiday that commemorates the anniversary of the first battles of the Revolutionary War. Re-enactments of these battles are held every year at Lexington Green in Lexington and at the Old North Bridge in Concord, MA. There is also a re-enactment of Paul Revere's ride.
In recent years Patriots Day has also become known as Marthon Monday. The Boston Marathon is run every year on this day and this year will mark the 113th running.
The Red Sox have played at home every year since 1959. The games starts at 11am so that just as the game is ending the runners from the Marathon are heading through Kenmore Square.
**There is also Patriot Day which remembers September 11th 2001 and is not related to this holiday*