The goban is simply a square piece of cloth, on which i sewed the grid (using my girlfriend's sewing machine). The stones are those cheap glass flat marbles that you find in decoration shops. (Excuse my poor english, I lack vocabulary, so feel free to rewrite this passage, you'd be welcome !)
This is picture of the goban itself.
The wooden board is not part of the goban, as I usually play on a table. But since we were outside, we had to find a solution
And this is a picture of the goban "in action", with the two players (I'm on the left).