A trad jazz band called Virus has been playing every Saturday afternoon 4.00pm-7.00pm at the Laundry bar on Johnston St since 2001. I used to go a lot about five years ago and then stopped. I recently went back and it was as good as ever. Entry is free with donations to the band encouraged via a big kettle they carry around during breaks. There’s comfy couches to sit on and space to dance at the front and it’s much better now thanks to the indoor smoking ban.
This article suggests that the older male jazz fans can be sleazy towards younger female dancers, but I have not witnessed any unpleasant scenes. Virus and the Laundry provide a friendly relaxing Saturday afternoon that slips effortlessly into evening.