I have been to a few pub crawls with chatters from a sports bar and I remember the first time I turned up, we all arranged to wear sports caps.
So I turned up, not knowing anyone, and wandered over to a guy and a girl wearing sports caps and introduced myself - and of course.....
....they had no idea who I was, they were tourists just having a beer. After that I headed straight to the bar to get a beer. Turned out everyone else was running late, and I was the first one there. But it was the beginning of many great pub crawls with my fellow chatters.
Not sure if you are allowed to wear caps in the club though...