Javelina Jundred, live.

Five laps of the Sonoran Desert, in costume

The Javelina Jundred runs the same desert loop five times, alternating direction, on Halloween weekend.

Aravaipa’s Javelina Jundred is the largest Halloween ultra in North America and a Western States Golden Ticket race. The course is a loop of the Pemberton Trail in McDowell Mountain Regional Park near Fountain Hills: a 22.3-mile opening lap on the Shallmo, Pemberton and Escondido trails, then four identical 19.4-mile laps run in alternating directions — the "washing machine" — with everything passing back through Javelina Jeadquarters each time. The 100 km is the first three laps; the Jackass Night Trail runs a single loop the evening before.

The lap format makes it the most social hundred in the sport, with a costumed crowd at headquarters all night, and the most watchable — but only if you know when the runner is coming round. On Livebib the loop is drawn once, the runner moves along it, and the arrival estimate for the next pass through headquarters keeps updating. One link, and nobody in the crew has to stand in the dust guessing.