As a child in the 80s, Ellie Hudon was rarely indoors. She had eight siblings and an extended family of forty—a clan too big for anybody’s backyard. So they hung out instead in Rowntree Mills Park, a serpentine 92-hectare greenspace that wends its way through Humber Summit, her North Toronto neighbourhood. Her fondest memories were of the relay competitions—epic triathlons, quadrathlons, and pentathlons, which included sack races and egg-and-spoon races—that she and her friends held i...