I don't know if it's been built already, or if the project ended up getting deserted.. But vegas was supposed to have a huge indoor skiing facility built into a caved/underground area.
Was going to be designed with pro athletes in mind as a way for them to train on jumps/pipe/rails in the off-season so there was going to be a pretty nice park built in it.
no idea whatever happened to it. The project might've got shut down, becuase I know there were a few agencies fighting it.