My friend once approached a girl in a club, and said 'I've lost my number, can I have yours?' sounds lame, but it actually worked.
Another friend of mine, a girl was approached by a bloke in a club and he said: 'Hey darling, do you want to me rock your world?' that didn't work, he got a glassful of vodka in his face.
I remember seeing a guy in a club, who went round asking all the girls if they could teach him to dance, they all said no. But then the next girl called her friend over, who was a gay man, and said that she could teach him, the man politely declined and walked away with a red face haha!