Playgrounds are everywhere. There are probably 10 of them within a kilometer of our leilighet. Almost every block has one tucked away somewhere. They aren't large like in the U.S., but they are ubiquitous. This reinforces the kid-friendly atmosphere of Trondheim (and Norway in general, I believe). Here's video of one of the unusual playthings on a playground. This is right in downtown Trondheim.