^^ ^^Mile End Park is super fun and the locals are pretty cool.
Rosemont is not far, but, in my opinion, lamest locals in MTL. I don't think I've ever had fun there.
The Pointe-aux-Trembles park is often empty, but it is a hassle to get up there.
The parks in the suburbs south of the island are super fun, but very suburban.
The Verdun park is fun as well. Everything there is small and its gets insanely crowded, but it can be fun.
Quebec City's park is awesome and there a few parks along the way up there that are fun as well.