Several years ago I went to visit my sister when she was living in Sioux Falls. I only spent half a day in the city before heading to Rapid City and it was drizzling the entire time.
We spent an afternoon in the Badlands.
One morning we got up early and went to Mount Rushmore and drove around the area including Custer State Park.
The funniest thing back then was seeing the soda machine in the bathroom.