We went earlier this summer and it was fantastic. They have cabins to rent and a campground, too. And lots of toddler-sized rides. It’s in Elysburg, PA, about 2.5 or 3 hours from Baltimore.
From a recent City Paper article that my husband wrote: “… you get rides that you haven’t seen for 25 years, or maybe have never seen before, sometimes for 70 or 80 cents a ride. You get delicious funnel cakes bigger than your face for a couple of bucks. You get a haunted-house ride and two roller coasters that are considered among the best of their kinds in the country. And you get in without paying an admission or parking fee, so you can actually leave this place with money in your pocket.” Here’s Knoebels’ website.