One that I haven't tried:
You:  "Hi - have you got any Welsh in you?"
She: "No"
You: "Cool.  Would you like some?"
One that I have tried (only once - whilst on holiday in Corfu - and it actually worked lol  

 ).  It's best not to try this on overweight victims (for reasons that will become apparent !!):
You:  "Hmm, let me guess I'd say you're 17 maybe 18".
She:  "Yea I'm 18".  (or whatever answer they give).
You:  "Cool, now I know your weight, let me try and guess your age".
This will prolly get 1 of 2 reactions.  You'll either get slapped and they'll walk off, or they'll giggle and see the funny side of it and you've just broken the ice and now have a great opportunity to get chatting.  Fortunately for me when I tried this (a long time ago lol  

 ), it was the latter  
