I mean "OS connections" is *very* broad...
Lots of various active FOSS communities in Sydney, though RH has been distant from most/all of them for quite some time (read into that as you will). We always welcome an individual curious ear though!
Most communities and gatherings won't be spinning up until the new year. Everything Open is in late Jan (CBR), and UG's/meetups resume in most places from February.
There's also #pyconau (BNE, CFP soon, sponsorships open now!) what might catch your curiosity. But hey I'm biased on the python front.