This is a nice conglomeration of pics and info from the last 2 Sand Box Show Down events…
First off…this isn’t an event for the faint of heart.  The sand is deep, the tunnels dark, dank, and dingy and nobody has trimmed any of the evil Arizona foliage nor marked the course.  
The first year only 2 people finished before dark.  Paddling fat tires through the sand was more than any of us could have expected.  Most people had some sort of mechanical either to their bike or body.  We all learned that when it comes to tire pressure under 10psi is a must and that horses tear up a wash something fierce!
Year two was more enjoyable.  Maybe we were better prepared or we just got lucky with the “trail” conditions.  The late summer rains put just enough of a crust on many parts of the washes that it could be ridden at a 15-20mph…except for that one narrow wash that stretched for 6-9 miles and didn’t have much more than 100yds straight of anything you could paddle faster than 3-5mph.
Luckily there was lots of alcohol to keep us from thinking about the pain and itching from all of the scratches from Mesquite, Catclaw and Palo Verdes…
If you have never ridden a Fat Bike (Surly Pugsley, Salsa Mukluk, Reeb, Black Sheep, etc) You are missing out on one of the most fun things you can do on a Bike in the Desert!  It opens a whole new world of terrain and it’s fun to be on Balloon Tires!