Nothing I can think off, most of the large
condos around here all have private playgrounds. There are paid play areas like, gymboree, and go go something at Dempsy hill or Tree house at Friven (the old tanglin post office).
The cost of the land around the top end of Orchard makes public playgrounds economically unfeasible.
Botanical gardens is huge should keep the kid lost for days.
Theres a huge playground area on the west coast park near Macdonalds. (bit of a trek from orchard though)