They polish their boards and then dash up the slopes, barefoot and fancy-free. New, all-terrain mountain boards are now adaptable to the rocky and grassy slopes of ski resorts and sand dunes. South Africa is lucky in that it has some of the best natural dunes in the world. Alexandria on the east coast has the most magnificent dune fields, but you'll need a permit to ride there. Namibia has been blessed in the dune department.
Dunes there can reach hundreds of metres high.
Swakopmund, Sossussvlei and Sandwich Harbour are reputed to be the stuff sandboarding legends are made of. If the slope is steep enough, anything will do, as long as it slides. Even a pizza - although I wouldn't want to eat it afterwards.