At times a low cost creative idea turns out to be much more effective than an expensive ad campaign. There are several examples of this in: Buzz Marketing: Get People to Talk About Your Stuff by Mark Hughes.
The author uses creative ideas to generate tremendous awareness of a product such as renaming a town half.com. Or putting ads on urinal cakes that say “stop pissing away all your money”.
Another example of buzz marketing is Starbucks. They have quite a small ad budget but they have become one of the most recognized brands in the world. Although this is probably due to the sheer volume of stores, they also use a lot of creative advertising to create buzz, such as putting a magnet of a Starbucks coffee cup on the top of a taxi causing people to run after the taxis. They also illuminated an entire skyscraper with green lights to promote the release of their Green Tea expresso drink.
These kind of efforts not only get lots of buzz but also are covered by the media, which is free advertising.