Do you know what day December 21 is, Tomorrow? The winter solstice — the shortest day of the year. And this time it falls on a Sunday. How about a little challenge? Let’s call it Midwinter Marathon Madness. :) It’s a marathon walking challenge where you design your own route and take care of everything yourself. The rule is simple: start at sunrise (or after), and finish at sunset. Technically, any distance counts as completion — but since “marathon” is in the name, the real goal is, of course, 42.