Hi, Deb!
We live about an hour from Marblehead, so we go there all the time. Kelley's Island is a very slow island with some rock inscriptions and glacial grooves. If you just want to sit around and relax, that's the island to go to. But, if you're ready to party, you need to head to Put-In-Bay. The Beer Barrel Saloon is the happening place. Make sure you head over relatively early if you want to rent a golf cart, which is the way to get around the island.
I don't know how old the kids are, but PIB has a place where kids can go to fish for free (I think they have to be under 12, but I'm not sure). There is also Heineman's winery where you can tour the Crystal Cave (for a fee) and then pay to sample some wines. Across the street from there is another cave with a miniature golf course out front. Perry's monument is there, too, and you can go up in that for a great view of the lake.
Back on the mainland, Cedar Point is a lot of fun. Make sure if you go and you want to spend 2 days that you get the 2 day pass which will get you into both Cedar Point and Soak City for about $70 for adults. There is also access to the beach by the Breakers that is free. Snoopy lives here, so there is 2 kids areas - 1 with Snoopy, and 1 with more generic kiddie rides. Of course, this is the roller coaster capital of the world, so you'll find plenty of fun coasters. When you're ready to cool off, Snoopy Rocks On Ice plays, along with several other musical revues, each with a different theme. There's plenty of food places other than your typical amusement park faire to eat at, including Johnny Rockets.
Let's see, another winery there is Mon Ami - it's on the mainland halfway between Port Clinton and Marblehead (they're only about 15 minutes apart). African Safari Wildlife Park is there where you drive your car through an animal sanctuary and can feed and pet the animals. Right near there is a new water park (I don't know the name for sure), and Marblehead also has a lighthouse you can tour on weekends. If the kids like trains, there is a place called Train-O-Rama that costs $5 to get into and has about 20 different model railroads set up.
Okay, onto the Yankees - hopefully they are there the time you are going, otherwise you will be seeing the Cleveland Indians playing whatever team is in town then.
I know, that was long, but I just wanted to let you know that you won't be hurting for things to do. If you have any other question, please just let me know!
