It's Smithsonian Museum Day time again, kids.< BornFrugal >
You can do a search for your state or city and find a participating museum or site to see that would ordinarily cost money for entry. https://www.smithsonianmag.com/museumday/
In the past they held the days twice a year, in March and September. Now they are only once a year and this Saturday is it. Only one ticket is available for each click but if you have friends or family members who want to go they can register separately.