Found this over at Engadget and thought it pretty funny. Some dude claims that in many cases you can enable an elevator's express mode by pressing the "Door Close" button and the floor you want to ride to. Everyone's elses selections (even those done before you) will be overwritten. Haven't tried it yet, but I definitely will the next time I use the elevator at my work.
More:
http://www.engadget.com/entry/1234000340052853/