My three have something called "summer playground". It's a community program that is free for kids 6-12, they get dropped of at the local school for crafts and games from 9a-12p and they have high school kids as counselers . They also have two preschool classes, one for 3 yr olds(Jesse) and a 4/5 yr old program(Jake), they cost $12 each for the whole summer. They each go for an hour and 15 minutes, 4 days a week. Josh has been going since kindergarden, and Jake went one year and loved it(they were full last year so he didn't get to go). Jesse is so excited because it's his first time and he ask every day if he gets to go to "summer skool" today?
Other then that we will spend time at the lake, my neighbors pool, the trails at the park,...who knows what else since a lot depends on how much extra $$$ we have.