I have done this once though, but I wouldn't really qualify this as solid game.
Go to the supermarket everyday (which I do anyways, horrible planner)
Pick the same girl everytime.
This is what I roughly remember from the conversations I had:
Start of with hi.
Next time, hi and some fluff.
Next, hi, compliment her on looks, fluff.
Next, hi, I've seen you around, you are on your way to become my favorite cashier girl

+ introduction
Next, hi Lisa, You have are racking up the points right now with that toothpaste smile and this time you even gave me enough change back :p (which I guess is as small as a neg can get)
Next, hi Lisa, *nothing* she asked me about her ranking today. I came up with some final task to be crowned queen of the cash register involving jumping trough various burning hoops, find the holy grail and ultimately slaying a dragon. Her looking at me with a wtf face. Me asking her last name so I could fb her and we could hang out sometime.
It worked, but obviously it's A going to take way too much time since she won't be working everyday. And B, odds are it only worked because she already felt some attraction to me.
So to wrap it all up, does anyone have a better experience, game plan or dream of the pinnacle of this unique type of game?