I have been doing a lot of thinking about this for a Whie Now and I can easily spot a chick flick now, like This new film 'The Sisterhood of The Traveling Pants', but as far as games for girls go, the closest we currently have is The Sims and Animal Crossing. Tetris did well and so did Dogz, but no games concept has flew directly over the heads of men and appealed intimately to girls before.
The endeavours of the crappy Barbie and Kate & Ashly games make an attempt, but these appeal to kids and not to a mature female mind. I am not going to go as far as to wear a bra and high heals to try and understand what girls want in a game, but I am looking at a difficult task. I know that girls have clear goal and I know that girls generally don't know what they want. So that leads me to believe they are just fickle. Maybe getting a girlfriend would help, I don't know, but a dressup game would be crap.