Fiji in 12 hours - What to do?

My girlfriend and I have a 12 hour layover (11:30am - 10:50pm) in Nadi on our way back to the states from Oz and would love to get even the tiniest taste of Fiji while we're there. We're young, outdoorsey, active, and into snorkelling and birding. Any good tips on what we could possibly see/do for an afternoon/evening on the island? Obviously, we're not going to see much, but a chance to get out of the airport and jump in the water or check out some birds up in the forest would be a welcome respit before our epic flight back to the States.

Thanks!

have look at this link

http://denarautransfers.com/nadi-day-tour

it is an option for u

Garden of the sleeping giant is worth a look, 10mins from the airport. Not overly adventerous, but a nice place to visit.