Most guys have seen the pick a number routine.
Guess a # between 1and 4 (most pick 3)
Then guess a # between 1 and 10 (most pick 7)
I haven't used this in field up until recently. I was watching a soccer game and talking to some girls just to pass the time that had family/friends playing.
Somewhere in the middle of the conversation:
HB: I don't like when guys played games.
Me: Well some games can be fun. In fact lets play one right now.
She gave me a contemptuous look and her eye twitched which I teased her for.
I did the routine, she guessed 3 and 7 and then I explained how the trick worked.
HB: Wow, you can already get into my mind, guess how good you'd be in bed.
Me: Ha ha, it's not exactly like that but pretty much.
She laughs.
It may have been beginners luck but it fun getting it right, especially the first time.