Got it in an email & it's on their facbook too, email said about the 20% off - not sure if that part is subscribers only but I'd be surprised if you couldn't talk your way around it:
Jack London - VIP Event- Thursday October 3 8pm
301 Swanston st Melbourne Vic
Exclusive 'Darling Downs' acoustic set upstairs at Sahara
featuring: Kim salmon (The Scientists) & Ron S Peno (Died Pretty)
8pm - 9pm
Like this post for a free drink on arrival
(Alternatively you might get away with emailing your full name to [email protected] before 5pm as that's what my email said to do - but that might be only for subscribers). Might be able to do both and get 2 drinks, who knows?
Email also said discount is valid online for tonight only using the code VIP20
combine with http://www.ozbargain.com.au/node/118348 :)