Nice sodding stunt, and I'm all for more parks and green space in theory, but where exactly is the empty lot in that picture, Charles? If it's within walking distance of the Capitol Hill light rail station currently under construction—and I think I recognize that asphalt (passed out there once or twice)—that's the wrong place for a new urban park. Undeveloped and underdeveloped land near Capitol Hill's new light rail station should be dedicated to transit-oriented development, i.e. new apartments, condos, more units of affordable housing, more ground-level retail, etc., even at the risk of a developer making a profit.
Saving empty lots near the new light rail station for green space—not set aside for housing—is anti-urban and anti-green.
We've got Cal Anderson, we've got Volunteer Park, and one day—a boy can dream—maybe we'll put a lid on I-5 between Pike and Pine have a nice new park there too. We don't need parks near the new light rail station.