James and I were able to visit White Sands while we were in New Mexico. I seriously love this place. It is so beautiful and unique. As you enter the National Park, the cars in front of you start driving really slow because the white sand looks like snow. Subconsciously you want to drive slow and be careful and you have to remind yourself that it is sand, haha!
The thing to do is bring some snow sleds and slide down the slopes. The last time I visited White Sands was June 2009, and that is exactly what we did. You can see pictures here. So fun!