When my husband was traveling for work

I joined FestivalNet.com which is for exhibitors, artists, etc. You can search their site and see what’s going on in any given area. I used it as a tool to find things to do in areas I was unfamiliar with and attended a number of events.
Maybe this will help locate things to do in your surrounding area that would be free to do. A search of our area within 30 miles has a pirate fest, mango festival, craft festival, street fairs, parades, music fests, etc.. I like the craft fairs as I always come back with a head full of ideas and they provide great motivation for repurposing things I already have on hand. I generally don’t duplicate what I see, but take things a step farther.
Also, whomever suggested joining a museum is spot-on. We did this when the kids were little but take note that they have a 90-mile rule – meaning that you didn’t get in free to places within 90 miles of your ‘home’ museum. Now, this was never, ever enforced in our experience but something to consider. We priced memberships at a number of museums, too, because a family membership at the best value we could find is $35 today. Another, for example is almost $100, so we went for the $35 membership with free access to the museum with a $100 membership price.