It's been a couple of months now since Sydney opened it's doors to the first Oxygen Bar! It's called Oxygen Bar Oxygen Station. I haven't tried this one myself yet, but I'm sure I would try it out the next time I have a visitor around. Although I am not quite sure how long the bar would last (just like the Ice Bar which was around Sydney a couple of years ago - but closed down). But then again, it is I think only meant to be around until end of July 2012.
Harbourside Shopping Centre
Darling Harbour NSW 2000