First, a joke.
-What did the Chilean fireman call his two children?
-Jose and... (The, erm, 'punch line' is at the bottom)
Anyway, just past Con Con are some reasonably large sand dunes. They're pretty cool to look at. But they're even more fun to drive over. I went last weekend with a friend.
For 2500 pesos you can access the beach in your car and then spend as long as you like destroying the environment in your big 4x4. I highly recommend it as it is a whole lot of fun.
Also fun is running down near vertical slopes and trying to keep your balance.
I suggest leaving your handbag in the car, though. There aren't any shops in the dunes.