Skateboards that incorporate a curved or arched board with wheel trucks and a cross member that may be repositioned on the board, with the board either in an arched upward or arched downward orientation. The cross member may have projections on its underside for locating with respect to a rail, such as at 90 degrees or 45 degrees with respect to the rail for sliding along the rail. The removable trucks may be replaced with such alternates as roller blade trucks and ice skate blade type of "truck." Also disclosed is safety clothing suitable for use when skateboarding or in other activities. The clothing has pockets in the inside thereof to removeably receive cushioning or energy absorbing material, typically in sheet form, such as closed cell foam, so as to be invisible to the casual observer, but to offer substantial protection to body parts such as hips, knees and the like. Various embodiments and embellishments are disclosed.