Well there is a whole huge thread on all kinds of openers you can use or so called "canned material" you can get inspiration from. First off, I'd like to point out what people call "Canned Material" they typically thing of those basic indirect openers we've heard a billion times some dude with peacock feathers wrote.
Truth be told "canned material" is anything that you have prepared in advance, that includes stuff you wrote, that is in your "can" or "bank" that you can pull out and use in situations like this. This is where proven canned material really shines. There is nothing special going on to comment on and you have some pre-prepared. Then again you could always try to come up with something on the fly about the girls - what they are wearing, doing, drinking, etc. but that can be a lot of stress. Go into your "can" and pick out something you feel good using.
There are all kinds of openers... situational openers, shock openers, sexual openers, indirect, direct, etc. Based on the vibe I get from you I would think something indirect or direct would probably be more up your alley but I could be wrong. The openers thread is a good way to get inspired to see things and then put them in YOUR words to try out. Just make sure you don't use someone else's lines word for word unless you can see yourself saying that naturally. Pick openers that compliment your style, don't mold yourself into someone else for the technique to work.