This would be fun to go to this weekend, but we already have 2 other things going on Saturday so we are just not going to be able to make it. Thought I would pass it along...
https://www.nbm.org/families-kids/festivals/foba.html
FREE. $5 donation suggested. Most appropriate for ages 4?12. Drop-In. Individual registration is not required. Formerly called the Festival of the Building Arts.