Updated

OAKLAND, Calif. -- Marijuana legalization advocates across the country are expected to light up during Tuesday's annual observance of 4/20, their movement's high holiday.

But San Francisco Bay area pot smokers got a jump start on the festivities.

IGrow, an Oakland pot gardening superstore, sponsored a "420 Eve" festival Monday afternoon. Several hundred revelers showed up to celebrate their drug of choice's growing commercial clout.

Allen St. Pierre with the National Organization for the Reform of Marijuana Laws says marijuana's steady growth from counterculture indulgence to mainstream acceptance will be evident in the nation on Tuesday.

Public displays of mass inhalation also are scheduled for Denver, Boston and Seattle.