A loud club can be a PUA's nightmare. Tough to spit game over the thumping of house music. In those situations, I have to turn to the smokers area which, in my part of the world, must be outdoors by law. Atleast it gives you a good opener:
"Hey, can I bum a cigarette?" .
Now, I am in a health profession, so when the set hears what I do, they inevitably say, "Hey, you do such and such for a living yet you smoke?" The question has come up enough times that I've formulated a pretty good answer. This answer is a little intellectual for the average HB, so I actually use it as my own shit-test to see if the target is smart enough for me (intelligence is as important as looks to me...well, almost as important). Here it is:
"See, I've got a theory on that. I've studied the effects of tobacco on the body and I've learned something interesting. First, cancer is caused by the same tobacco product being used constantly for many, many years. Its gotta be nonstop because your body can actually recover from pre-cancer damage. Second, each type of tobacco product primarily causes a different type of cancer. Chew causes mouth cancer, cigars throat cancer, and this little guy [hold up cigarette] causes lung cancer. Do you see where I'm going with this? ROTATE! Every year do a different tobacco product: chew or dip one year, cigarettes another, cigars another. Repeat the cycle and you'll never get cancer in any one part of your body."
Let them know that its just a theory you have. If the target is smart, she'll think you are witty. If she looks like she's about to have a seizure over the big words and fancy ideas in your routine, I typically move on. So is the theory true? Hell if I know, I just made it up. But the logic is true. I met a great girl with this one and brought it up again during my phone/text message game. She became great to me in even more ways.
Oh yea, I doubt you have to be in the health profession for this to work.