https://github.com/davepinch/pinchy.cc/blob/master/content/streams/the-last-spark/0/the-last-spark.md
Free guided public tours are available daily from May 1 through Sept 30, except Mondays and Tuesdays when viistor center is closed. Free tours start at 2:00 pm in the visitor center theater and last about an hour. You can join a tour anytime, no registrations are required.