walkathon

noun

1. A long-distance walk, either as a race or in aid of charity.

   “[In 1946.] Some tattered walkathon tune of the early thirties went banging like a one-wheeled Good Humor cart of those same years through his head as the cards slipped mechanically about the board and his fingers went lightly dividing change in the middle, taking the house's percentage without making the winner too sharply aware of the cut.”