"Almost every person hath some hobby horse or other wherein he prides himself."-Sir Matthew Hale, Contemplations Moral and Divine, 1676
The Osney residents made hobby horses(and jolly fine, they were too), and then had a race.
The concept of making and riding a hobby horse as a pastime that someone follows with almost obsessive focus, goes back to the 1600's.
Of course, today, the phrase describing an obsessive pastime is shortened to just "A hobby"
Canon EOS-1D Mark IV