Theme
Out & About
Logistics
Outdoor Friendly
Long Activity
Low Cost or Free
Live Sport
Watching sport on telly is fine, but it doesn't match the excitement and tension of being there live.
Although your mind might drift towards the big leagues like the NRL, don't forget smaller local matches which are usually cheap or free.
It's also worth thinking about a range of sports outside the typical spectator ones, for example lawn bowls, squash, or rowing.
Australia is a big country, so using Google to find local options is going to come in handy.