Oh there is the Atmospherium Planetarium that is very fun and the showings change so check what they are showing. It is very near the downtown area. Also there is the Wilbur May Museum of all his travels and part of his furnishings in the Rancho San Rafael park. Also near the downtown area and very interesting to see.
If you feel like driving 40 minutes you could visit a real old time mining and gambling town up in Virginia City. The turn off for it has the signage if you follow south Virginia. It is called Geiger Grade.