Buy a day ferry ticket and visit Watsons Bay , have fish n chips looking over the city - Go over to Manly & go snorkeling .
Take a ferry down the river to Paramatta .
Visit one of the many markets & try a $10 chinese meal .
Spend time down near the Opera house - grab a bottle of Chardonay & a snack & relax in the park overlooking the water .
This is some of what we did in Sydney !