Frisbee Go
A net on the grass and the stones are frisbees, to be thrown from a (little) distance.
At the Tuchola (PL) Go Congress 2004:
(big: http://matthieu.walraet.net/go/tuchola2004/big/350-5007_IMG.JPG)
and
(small: http://foto.luftbrandzlung.org/albums/EGC2004-Naoyoyuki_Kai_1/IMG_0009.thumb.jpg)
(big: http://foto.luftbrandzlung.org/albums/EGC2004-Naoyoyuki_Kai_1/IMG_0009.sized.jpg)
(small: http://foto.luftbrandzlung.org/albums/EGC2004-Naoyoyuki_Kai/EGC2004-Naoyoyuki_Kai_1.highlight.jpg)
(big: http://foto.luftbrandzlung.org/albums/EGC2004-Naoyoyuki_Kai_1/IMG_0010.sized.jpg)