As it relates to current events, washing your hands can help prevent the spread of H1N1, but it also helps prevent the spread of numerous other illnesses. In the case of medical professionals, washing their hands can literally be a matter of life or death for their patients. In Super Freakonomics, the authors reveal that medical workers (particularly doctors) are not particularly good at washing their hands.
The authors describe an effective method employed by Cedars-Sinai. The medical center set the computer screensavers to pictures of bacteria-laden hand cultures taken of physicians' hands. The book reports that hand-hygiene compliance "shot up to nearly 100 percent." The Freakonomics blog reports that "Clean Hand programs are now the norm at hospitals."
Admittedly, the audience at a hospital may be more responsive to a bacteria culture than the average, say accountant (as an example). But perhaps there is something to this screensaver thing. Maybe it's "wash your hands to help stop H1N1" one day, and "ummm, yeah, we're putting new cover sheets on all the TPS reports*" the next. The possibilities are endless!
Sidenote: ABC posted a 20/20 video showing the actual hand-culture screensavers. It also includes an interview with the Super Freakonomics authors, the dangers of dirty neckties, and disturbing footage of a woman with a flesh-eating disease in her stomach.
* That's a reference to the movie Office Space.