Here are a few eco friendly ideas you can do with that special guy.
Rent bikes and cruise the town. A great way to spend your outdoor family time, plus its cheap, green and gives you some exercise.
Go for a hike. Check out this list of Australian National Parks, pack a picnic, find a cool spot and check it out.
Plant a tree with or for your Dad. Research what trees are endemic to the area you live in, stop by a nursery and plant it together. You'll have something that will be around for years to come. For a global perspective, buying trees will help combat desertification, climate change and deforestation.
Visit a nursery. Nothing says 'inspiration' like visiting a nursery. Take the time and maybe plan an new garden bed or project over the weekend. Nurseries Australia have a list of nurseries in all states.
Spend some time in the garden. Its Spring! Get out in the garden, weed away those Winter weeds, prepare your veggie beds, turn the compost. Go on, smell the fresh air.
Swing by a farmers market. Cut down on greenhouse emissions and support your local growers and producers. Everything is beautifully fresh, homegrown and handmade. Every area has a farmer's market, but if your not sure where to go, take a look at the farmers market online directory.
Cook him breakfast in bed. An oldie but a goodie. Make sure its his favorite breakfast and organic! He'll feel pampered and special, a great way to start his day.
Above all, remember, its the thought that counts and what better way to show you care, than to spend some quality time with the old man!