Yeah the place is pretty hot but you get that dont you. We dont have any hills in or around darwin so DH ridn is out. The council are starting with the small skate park thing, there is 3 at the moment but the are pretty small. There is 3 BMX tracks to which you can ride on providing you wear safety equipment.
Apart from that you can always find things that you can play around on. Can I ask why you chose darwin? or are you in the army?