If you want to see Brisbane, catch a CityCat (high speed ferry) and go for a run along the Brisbane river. There is also the Story Bridge Climb, and you can do a walk outside the M1 building on the Gold Coast (Look for the tallest building along the beach). If you can get to the Sunshine Coast (North of Brisbane) you can goto Australia Zoo (Steve Erwins place) and see how many things can kill you in Australia.