I had the opportunity to examine malware whose initial infection vector was a car windshield flier with a website address. The malicious programs were run-of-the-mill; however, the use of fliers was an innovative way of social-engineering potential victims into visiting a malicious website.
Several days ago, yellow fliers were placed on the cards in Grand Forks, ND. They stated:
PARKING VIOLATION This vehicle is in violation of standard parking regulations. To view pictures with information about your parking preferences, go to website-redacted
Source: http://isc.sans.org/diary.html?storyid=5797