Admit it: You've taken key cards from hotels. Sure, Sometimes you forget to give them back, but other times, it's just a great memento. But you probably don't have more than Steve Rushmore, founder of the hospitality-consulting firm HVS, who has collected them for 30 years.

The cards serve as 2-inch-by-3-inch canvases for the corporate art of branding. Lately, they've doubled as ad space for everything from films to local restaurants. Check out a few of our favorites.

The first hotel to install a recodable lock 30 years ago was the Westin Peachtree Plaza in Atlanta.

Austin, Texas

Denver, Colorado

At sea

New York City

Kowloon, Hong Kong

Las Vegas, Nevada

Pickerington, Ohio

Buenos Aires, Argentina

Dearborn, Michigan

Carlsbad, California

Los Angeles, California