I don't know the direct Irvine area, but I'm close (Downtown L.A.) enough.
i've been to a show in fullerton, at a place called "the santa fe express cafe" i think.
very nice show, near (as in right next to (as in 30 feet from)) the train tracks and metrolink rails. They have houkahs, alchohol, one bathroom, weak coffee, but they have live bands from all styles ska, emo, punk, rock, indie, smooth, etc... every weekend. did i meantion they were realy close to the train tracks too?