Javalina 12 Hour Run in McDowell Mountain Park.
I've done six of the 48-mile variety in the Grand Canyon (between 13 hrs 50 min to 18+ hrs), but never anything more than 26.2 with a race number pinned to my chest. Guess that'll change this September. :-)
Now...to train in the heat of the Arizona Summer for some serious long-@$$ distances. Time to get my training schedule nailed down and be in good shape - or else! More to come!