slalom skateboarding is how I spend the summer. There are races all over the world and the sport is growing really quickly. The body positioning for slalom is very similar to alpine riding( toes forward, shoulders facing forward, perpedicular shoulders to riding surface). Giant slalom would be closest to alpine, some of the tight slalom have the racers making 4-6 truns every second!.
Heres a little clip of me training last summer.
http://www.vidiLife.com/reloc.cfm?cryp=010-5AA188D0-5CEB-4A59-BD5C-2
Its a blast and the people that do it are even cooler.
Try it out! Lots of people that have never skated before do well trying slalom, and some of the racers push 50 years old, so its something you can do for as long as you can snowboard.