They have everything from sports, art exhibits, toddler activities, music in the park concerts, etc.
Many events are free or low cost.
It will depend on the facility in your area but the best ones have creative directors that provide quality entertainment for the whole family seven days a week. I never go to the movies anymore. The popcorn is too expensive, the theatres too crowded, the lines too long. My opinion, but the savings WAY outweighs the benefits a theatre has to offer. If your child needs sports equipment, try a second hand sports store.