This is a pretty simple and silly game to make up with a prospective girl that you can develop over time . Just like in "Who's line is it anyway" the points don't matter. Reward her with "points" when she does something cute, nice or funny and neg her by minusing points when she fucks up, or even when she doesn't. Keep her guessing as to what the rules are and make them up as you go along.

It may sound stupid but I've tried it several times and have had pretty good results. You can even make up incentives and promise her some kind of prize. But obviously you don't want to over do it to the point where she doesn't give a fuck about the points or some made up prize.

The last girl I used it on, I told her if she got 50 points she'd win a Chinese Finger Trap !

The best part about this game is that you can continue to use it as an ongoing inside joke or just 1 night at a party (tell her a kiss on the cheek is worth X, singing a song is worth Y, hitting that beer pong cup is Z)