A tall, lanky, rather
dark Black person (hence the term, Monday) who partakes in a
26.2 mile long running competition. They are typically, but not always, imported from Ethiopia and Kenya.
White Guy 1: "Hey, Murphy, who's that Black guy? Is he on the
Celtics?"
White Guy 2: "Nah
McDonough, today's the Boston Marathon; it's one of those Marathon
Mondays."