My stock canned opener is the Man-Bag Opener (which I take full credit for lol):

You: Hey guys, do you think man-bags are sexy?
Girl 1: No I think they're gay!
Girl 2: I like them
You: You like them? High five! I like you the best!
You: The reason I'm asking is cos I've got a man bag and I'll be honest, it's fcuking sexy, but our friend's gone a bit too metrosexual and he's started wearing make up and we swear he's got a girl's handbag but we're not 100%. Is that weird?
Them: Blah blah blah
You: Cheers guys, I better get back to my friends. Oh wait, just out of curiosity, how do you guys know each other?

etc...

That's if you like stock openers of course. I now prefer jumping into a group of girls and shouting the first thing that comes into my head. Quite often it's "PENIS!" cos we all know that's a funny word. They love that they do.