So this is going to happen next year:

Mark your calendars for Sunday June 16, 2013. Rachel and I signed up for Tough Mudder Colorado 2013.

This should be good as long as we can handle the hot, dry Colorado summers and get acclimated to the altitude quick enough. Last time I was in Colorado, I hiked a 14ner and ended up suffering from altitude sickness, which—while an interesting case study in how my body works—was not fun to deal with.