Saw the request for game types on the homepage, and two come to mind:
9 ball: balls are racked in a diamond shape, with the 9 ball in the middle. After the break, the lowest numbered ball on the table must be hit first (ie -- if the 1, 3, 4, 5, 8, and 9 are on the table, the cue must hit the 1 ball before any other ball). If the lowest numbered ball isn't hit first, or if no balls are hit, it's a table scratch and the opposing player can put the ball anywhere on the table. Object of the game is to be the player to sink the 9 ball. You can play a combo shot off the lowest numbered ball, or clear all the other balls off the table.
Cut-throat: 3 Player game. Player 1 gets balls 1-5, Player 2 6-10 and player 3 11-15. Object of the game is to sink your opponents balls. Play alternates like regular 8-ball between all 3 players. If all your balls are sunk, you are eliminated from the game. Play ends when only one player's balls are on the table. The varient on this is if a player scratches, each of the other player gets to put one of their balls back on the table. (ie -- Player 1 scratches, the sunk 8 ball and 14 ball get to come back on the table).
That's usually what my friends and I will play. Hope that helps. Let me know if those don't make sense or you want me to test the logic in the game or something.