My kids went ducky. England's Blackpool This was such a hit with my kids that they declared it better than Disneyland. Right across from the Copenhagen train station. Near Arhus, Denmark. Thirty minutes from Paris by suburban train.
Admission is free and rides cost a couple of pounds each.
A popular waterpark called Sand Castle is just across the street. Ski slopes scattered throughout Europe are outfitted with concrete bobsled courses. You sit with a brake stick between your legs. Push to go fast. Pull to stop.