Really want to enjoy summer but don't want to pay through the nose for tickets and other fees? Get the family together and think about these things:
City parks are the cheapest (read "free") fun. Some have tennis courts and baseball diamonds. You don't have to be professional or even good. You don't even have to know the game well to have fun. Find a court or diamond that isn't being used, rent some gear if you have to, and have a family game or two.
Picnics anywhere are refreshing, even if uninvited ants decide to attend. Take some binoculars with you, lots of water and sunscreen. Eat dessert first so it won't get too hot in the sun. Why not? It's fun time!
Check out your city's civic/activity center and find out about free days or free activities. Ask about reduced fees for families, senior citizens and/or students.
Don't miss a parade! Keep up on what's happening for free in your area. Most towns have websites where they have calendars of events like parades and other free celebrations.
Again, check the park schedules. Many towns have free programs of various kinds, from concerts and plays to baseball games and tournaments of different kinds.
Go for a walk. Get the family together when it's cool enough and walk around your neighborhood. Take your time, smell the roses and maybe even get to know a few neighbors. If the kids balk, make it a game by giving them a list of things to look for and pencil or crayon to mark them off. No prizes or competition, but try to make it fun.
More ideas here:
Inexpensive Family Fun
Free Family Fun