Mate, if there is one touristy thing to do it's book a bridge climb, you WILL love it.
Ask me nicely and I'll take you for a fang around the harbour on the 21, it is the best place you could ever want to ski.
If your with a lady then a shopping trip into CBD, George St and QVB building is sure to impress, if scenery is your thing then Blue Mountains and surrounding area will blow you away.
Motorsport, book yourself a few hotlaps around Eastern Creek in a V8 Supercar
Mate, up to Brissy or Goldcoast and you will gain 5-10c and you can do theme parks if you have kids, Seaworld, Dreamworld, Wet n Wild, White Water World (lots of worlds).
If your into bikes hire a sports and do the twisties or a Harley and cruise the countryside.
You will be spoilt for choice.
Start your planning.