2nd Saturday Downtown, Tucson’s urban street fest, will be hosting its monthly event on Saturday December 14, from 2 to 8 p.m.
Full schedule here: http://www.2ndsaturdaysdowntown.com/event-info/schedule/
Of course, you can always stay on longer at the restaurants/bars/theaters on E. Congress St. for more pre-holiday fun.
Over at the historic Train Depot, one of my favorite Christmas movies:
Kids Area w/Cinema La Placita & Southern AZ Transportation Museum
414 N. Toole Ave. @ 5th Ave.