We did a 3-hour quad bike/sandboard outing -- an hour of ATV-ing thru the dunes, a chance to do as many sandboarding runs as you were willing to make the climb back up :-) , and another hour of ATV-ing back. Matthew took great care of us, the scenery was stunning, and we were each able to take the dunes as aggressively or as conservatively as we were comfortable doing.
The next afternoon, we returned to do a short (30-minute) camel ride out into the dunes. Ronald led us on Abraham, Moses, and Steven, and was happy to answer all of our questions about these camels.
We loved our activities with Desert Explorers, and I found them to be a top-notch operation. Guides were personable and knowledgeable, I liked the emphasis on basic rules and safety, and the camels seem to be treated very well. Highly recommend!