If the young ones are getting fidgety, make tracks to Childrens Museum of South Dakota. With plenty of interactive exhibits and displays, this place makes learning exciting.
You'll be spoiled for sightseeing choice when staying in Brookings. Children's Museum of South Dakota is a good place to kick off here, but there are plenty of other worthwhile spots to consider. South Dakota State University, Swiftel Center, and McCrory Gardens are close to the interactive exhibit for kids and will top off your day nicely.