I recommend visiting the Gorky Park in Moscow (go to metro station "Park Kultury' and then cross the Moskva river by bridge).
It has been extensively renovated. There are no more extreme rides, but many cool chill-out areas and sport facilities instead.
Open air cinema, water bike rentals, places for sunbathing and a lot more.
Here is a good blog post about the park: Фотопутешествия и еще. - Лучшее место в Москве (photos 01-03 show park before renovation, don't be misled )