When he was a wee lad, FLG's favorite playground was the Ancient Playground in Central Park. The pyramid was the coolest part. The NYTimes tells him that the playground has been leveled, but will reopen -- thank goodness.
In point of fact, Central Park has several cool playgrounds. The Adventure Playground is FLG's second favorite. He never actually played there, but it looks really cool. The Wild West Playground he is less enthusiastic about.
Other playgrounds that have caught FLG's notice: The San Diego Children's Museum Playground, Honey, I Shrunk the Kids at DisneyWorld, and the Disneyland Hotel Pool, which is pretty much a playground.