Riding freight trains is closest parallel to skateboarding I've found. Getting on and/or off (especially while moving) is like landing tricks. It's an individual endeavor but you're likely to find a crew of dedicated riders. There's spots to search for - train yards and crew changes. Different cars = different terrain. You've got grainers, gondolas, good old fashioned box cars, piggy backs,48' and 53' container wells, shit you can ride the unoccupied engines (units). Then there's the travel aspect, slams, cops, obviously the adrenaline factor is high.
Also a lot of waiting around doing nothing, because of course sometimes skateboarding involves not skateboarding