[ume]

Tokyo (not sure about the rest of Japan) has similar with a number of 'play parks' within larger parks. Rope swings, makeshift slides, saws, hammers and nails abound. The kids come back smelling of smoke from the communal bonfire though...

See http://playpark.jp (Japanese only)

[m_mueller]

also their normal playgrounds are nice. Tarzan swings, metal bar jungle jims, wood and metal slide houses and fenced in sandboxes are standard, plus they pretty much all have public toilets and water fountains. In general I find infrastructure for families great here, even in such a crowded place.

[dasil003]

Reminds me of the Berkeley Adventure Playground.