Quad biking in the Makgadikgadi Pans in Botswana is available from the Uncharted Africa camps - Jack's Camp, San Camp and Camp Kalahari. I stayed at Camp Kalahari (the most affordable of the three) and really enjoyed it's simplicity and charm. Fly into Maun and book a scheduled flight or a charter to the camps. Quad biking is seasonal and cannot be guaranteed.
Spent the morning visiting the habituated meerkats near Camp Kalahari. The little guys are extremely interactive, and depending on their mood and hunger levels first thing in the morning, they'll hang out for quite a while and maybe even use your head as a look-out tower. Only some meerkat families are habituated, so make sure the camp you are visiting has access to a habituated family if you want to get an up-close look.