Dude! There is nothing cheaper than free, and free is one concept that truly befits the sport of skateboarding, which, at its best, has no rules. That's exactly how things work at this city-built facility, whose smooth expanses of concrete bowls and ramps were opened to the public last summer. The fruits of a project spearheaded by city councilwoman Joyce Foster and a bunch of restless skateboard kids who had been ousted from the 16th Street Mall in the name of progress, the approximately 60,000-square-foot park is touted to be the largest free paradise of its kind in the nation. Equally expansive are its 5 a.m. to 11 p.m. daily operating hours. Helmets are not required, so grind at your own risk!