Ride a gondola up to the Atherton Tablelands, giving you views down into the canopy of tropical rainforest. The ride is 45 minutes to the top (7.5 km), 1 1/2 hours round trip. You'll reach a height of 1788 feet at the highest station of Red Peak. There are two places where you can get out and walk some nice but short trails, and of course the town Kuranda at the top end of the skyrail is a nice town to walk around with plenty of things to do.
The ride itself is wonderful as you peer down into the canopy, seeing plenty of birds and clouds of butterflies as well as the wonderful scenery. I'd suggest using the way up to focus your attention on the forest below, and the way back to enjoy the scenic views across the mountains and out to sea.
The first stop is Red Peak Station, where you get great views across the Barron River valley. Here you are in the heart of the tropical rainforest that you have been enjoying on the way up.
The second stop is Barron Falls Station, highlighted of course by Barron Falls and Barron Gorge. Quite impressive, and very beautiful.
At the top you find yourself in Kuranda, a pleasant enough town with lots of good aboriginal art galleries, souvenir shops, and restaurants. There's lots of good walks in this area too. Check out the maps when you get off the skyrail. You can take river cruises up here too.
The overall experience is quite nice. This is a good, easy way to see and appreciate the rainforest - if you don't have the time or desire to do some hiking and camping in the Tablelands, then do this. If you are doing those things you still might find this a good introduction to it all.
Roundtrip on the skyrail is $46 AUS adult, $23 child. To take the skyrail up and the train back it's $63 adult, $31 child. There are other packages also. Check out their website here for more info.