I was disappointed to see the other posting regarding Desert Adventures' jeep tours. It must have been a very windy day because I've been out on several of Desert Adventures' jeep tours and they are all incredible! Their guides are super knowledgeable and they take you places and show you things you would never imagine existed in the desert.
If you like rugged adventure, check out their new Joshua Tree Extreme tour. It climbs to the Joshua Tree National Park the back (and extreme) way. For those who want something a little milder, I'd recommend their San Andreas Fault Earthquake tour. No matter which tour you choose, though, you are in for the adventure of a life time.
I HIGHLY recommend all of Desert Adventures' jeep tours -- they are the best anywhere!