There have probably been a million threads on this but my net-fu is so weak I couldn’t find them. Anyway…
Say you’re in a loud and busy club or bar and a particularly attractive gal or guy catches your eye. What’s your favourite conversation opener/joke/ice breaker? Mine is a little bit silly, but it usually gets a laugh. If I see a girl with a particularly elegant dress I might say something like “Excuse me, I get the feeling we’ve probably got a lot in common. I even have that outfit” and then procede with requisite introductions, small talk, rapport building etc…
I’ve never used this one but a friend does and I think it’s brilliant. Go up to your target and say “You look really familiar. How do I know you?” Puts the guy (or gal) at ease 'cause they assume you’re an aquaintance and they start mentioning all the places they hang out and activities they do so you have an instant conversation.