You can always do Mystery's ESP. Ask her, "Do you believe in ESP? YES NO MAYBE WHATEVER "Great, I have a test for you!" "Let me see your hands, and close your eyes!" (Good compliance test) "Don't tell me what it is, but think of a Number from 1-4 quickly, got it?" "3" Don't let her respond to much outside of yes or no. Right away say, "Great, no pick a number from 1-10, and don't tell me, got it?" "7"

Reason you pick 3 & 7.

#3 - 90% of people pick this when forced to do it quickly. People hate choosing 1 &4 just because you said them, and #2 is an obvious choice in the middle.
#7- is picked about 70% of the time.

If you get both right - See positive proof ESP does exist
If you get one right - See you never know what's out there
IF you get none right - I can't believe you believe in those silly things, or I knew you where to smart to fall for that ESP gag.

Actually one of the most powerful cold read isn't that at all, it's called an Equivoque or Magian's Choice whereby you make the girl think that she picked a number all by herself but really it was you who picked it in advance.

why do you need all these games?

I don't think most people use these games to build attraction at all. The point is to give blundering talkers like me something to introduce into a conversation, which in a way removes the first and most devistating block in any guys subconcious, approach anxiety!