What a super fun experience! Grover Beach, California is one of the few places left in the United States where you can still ride ATV on the sand dunes. We opted for the hour long Hummer tour and it was one of the most unique and exciting things we've ever done as a family. A guide drove us down to the beach and drove us all over the dunes...sometimes sideways, sometimes backwards, sometimes entirely fast, and sometimes in several feet of water. They are insured and you have to sign a waiver before you go. You will come back with sand in your ears (and everywhere else) but it's totally worth it!!