A free online Flash or Shockwave game, around 8 years ago.
Octagonal shaped playing area with a cross made of pegs in the middle, you and your computer opponent had some marbles that started out on either side of the cross. You had to aim your marbles into a goal which was a hole on your opponents side of the cross while protecting your own goal from your opponent.
I seem to remember there was a bug in that if you lost it announced you'd won, and vice versa.
Great gameplay, and way ahead of its time - you lost your game if your internet connection went down, just like the fancy modern games do