Thousands of people turned out over the weekend for Seattle's two-day marijuana festival known as Hempfest.

Each year, organizers use clothing and speeches to promote their efforts to get pot legalized, and more families and "mainstream" supporters joined them this time. And this year, organizers have more reason to believe there will soon be a change in marijuana policy.

Supporters, like Hempfest organizer Mason Tvert, have long argued that those under the influence of marijuana are in a much different state than those who use alcohol. "There's no reason why we shouldn't be treating it like alcohol and generating revenue and saving in the criminal justice system."

Mason Tvert, executive director of SAFER (Safer Alternative For Enjoyable Recreation), which ran a successful 2005 campaign to legalize possession of up to one ounce of marijuana in Denver, has long been the merry prankster of Colorado weed activists -- a prankster who knows how to have serious impact. When photos surfaced of Governor Bill Ritter's son hitting the booze at a governor's mansion party, Tvert and his posse threw a media-grabbing kegger on the mansion lawn to prove the point that the encouragement of alcohol but not pot was a total party foul. He was also responsible for arguably the most successful billboard that never actually existed: In 2005, as part of the Denver pot legalization campaign, SAFER proposed a billboard celebrating Miami Dolphins running back Ricky Williams, who'd been suspended for marijuana use. The billboard attracted national attention -- even though Tvert never actually put it up.