The game is conceptually similar to Othello, in that you're placing white and black pieces on the grid, and flipping your opponent's pieces to your own color. But this one works with rings, instead of lines.
Consider a Go board. Each point can be considered to rest on eight different 3 x 3 "rings", like this:
. . x 1 x . . . . x . x . . . . x x x . .
Point 1 is in the ring shown; it's also in seven other rings, in each of the possible positions within a ring. (Points on the edge of the board will, obviously, be contained in fewer rings.)
On your move, you place a piece of your color on the board. If that piece completes a ring, then all pieces in that ring are flipped to your color. When the board is filled, the player with the most pieces of his color wins.
That's the basics. There are some options to consider for tuning:
-- You might only flip the pieces that are adjacent to the finishing one that are of the other color. For example, in this setup:
. . w 2 w . . . . b . w . . . . W W b . .
If black plays at point 2, then only the points marked "w" are flipped, but not the ones marked "W". This is closer to the Othello rule. My suspicion is that it complicates things for no good reason, though.
-- I suspect intuitively that this game would be best played on a triangle grid, with hex rings of 6 points each. But Go boards are easier to obtain.
-- I don't know what the optimal size for a game is. I'm sure that a full Go board is pointlessly large.
I don't know if the game is any good, but I'll have to try it out sometime and see. If anyone else experiments with it, tell me what you find.