These small advertising boards always seem to be tied to railings, and they're always for random club nights at places I've never heard of.
I haven't been out clubbing for a very long time anyway, but even if I still was, who actually goes to these things? I've always found it very strange.
For some reason I only ever notice them when I'm in a car or a bus, usually on a long journey. I never see them when I'm walking locally.