Consisting of 26 miles, 20,000 runners and 450,000 onlookers, the Boston Marathon is the oldest annually contested race of its length in America. And, though there are ways to get from Hopkinton to the Back Bay that don't involve months of rigorous training, for many there's no equal to the exhilaration of testing one's ability against this course. Among the enclaves the race traverses are Framingham (where an errant train once stalled all but six of the competitors), Wellesley (home to the infamous ''Screech Tunnel,'' a sonic phenomenon created by volunteer cheerleaders from local schools), Newton (marked by Heartbreak Hill, the rise that separates the winners from the also-rans) and Brighton (featuring BU's ear-splitting spin on Screech Tunnel).

The last stretch leads runners past the packed Fenway (where a Red Sox game is traditionally underway) before proceeding up Boylston to a terminus on the street outside Boston Public Library. For some participants, these multiple miles are merely an excuse to schmooze with other athletes -- an inclination that is accommodated at an endless round of satellite parties, panels and pasta dinners. These meet-and-greets may also be your only chance to get a glimpse of the Kenyan contenders who often sweep the race. -- Julia Clinger