Just a though... I use my Forerunner 305 most times I go for a push (PUSH: to go for a ride on a skateboard or longboard). It's become a fun cross-training activity to my running and is one heck of a core workout with balance and control elements too.
When I upload my "push" to Garmin Connect and QuickEdit, the closest "Activity" under "Other" is "Skating" (and I think you mean the kind with ice).
If you doubt the growing popularity of longboarding, I suggest you Google "ROGUE 20KM Longboarding Race 2011" and watch the YouTube video.
Bryce (aka Lumpy)