Where can we vacation in ohio on a budget?

What are some ideas for summer vacation to do with children, that I can do on a cheap budget? We live in Ohio and would like to treat my kids to something this summer, but due to gas prices need to stay inside the state.

Do they like science? This sounds really cool:

Great Lakes Science Center –Visiting the largest hands-on science centers in the country is just the beginning of your excitement at the Great Lakes Science Center. If science is your passion then the interactive exhibits that cover numerous topics will blow your mind. View an 8-foot tall tornado, pilot a blimp or take a turn at virtual soccer. Visitors to the center should also take in a film at the Omniplex Theater.

The beaches in Mason, Ohio seem nice too:

The Beach Warterpark, perfect on a hot summer day, also has a high-energy winter personality which makes it an ideal escape for families. From old-fashioned carriage ride and reindeer at Santa's Village to live bands, carolers and a production by Madcap Puppet Theater, the activities are tempting. See the Polar Express miniature train display; toboggan down Cool Runnings slide; take an Arctic paddleboat cruise.

Hope that helps!

You could go to the rock and roll hall of fame? or cedar point. idk how cheap those would be though.

I use to love to go to the cincinattii zoo! They have a family day! Where its some what cheap then