Flickr has a seemingly endless collection of vintage masks, from The Wizard of Oz to creepy 1950s pulp-fiction looking characters. Those Dick Tracy comic strip faces are downright outsider-art weird.
Above are Gomez, Lurch, and Uncle Fester from the Addams Family (yikes!). The Addams Family masks were used by the Ringling Brothers and Barnum & Bailey circus. (Thank you to Brechtbug)