Howard Sherman's blog has an article about small local amusement parks. When I was a kid here in Portland, the local park that we loved was Oaks Park, on the East bank of the Willamette River. Though my father did not like amusement parks, he was nice enough to take me and my brother there occasionally. Oaks Park also had roller skating, and one area of the floor had some undulating bumps, kind of like waves.
Though the Oaks Park of my youth didn't have the huge, spectacular rides that some of the nationally known parks had, it was still great fun, and the convenience of it (only a 15 minute drive from home) was very appealing.