We missed free museum day this year because it was very close to the due date of our newest addition to the family. With cheap flights, it might have been fun to do a destination museum visit, like we did last year, but planned this time.
What I have noticed over the years of doing this is that a number of museums in the list are already free on a regular basis (but may ask for donations)
The search page, if it is still functional, looks like this (including some of the search criteria for example)
If it works, you can see which ones are already free but if not, you may need to search around to find some free activities in your area.
Until Next year!