go for the classic " i bet i can make u say black".
you start pointing at things and asking her what the colour is. when she says blue you say i win. shes hopefully says " i thought you said you couldnt make me say black" or something similar
YOU WIN
Or the simple but effective "i bet i can guess the number your thinking of"
PUA: i bet i could read your mind
HB: . . .
PUA: ok, think of a number
HB: (e.g. 10)
now remember that number as it is critical. simply tell her to add and take away numbers from her original number. add up the numbers you tell her (e.g. add 10 ,
you remember 10, now take away 4, remember 6, etc)
do that for a bit then right at the end tell her to take away her original number, and the answer will be the number you have in your head.
it works so well

*FEILD TESTED*