The Infamous Rose-Scented Stamp of Bhutan.
In the past few decades, in order to raise revenue, postal administration of various countries have issued a growing number of …. scented stamps!
As far as how the stamp above evolved, “The tiny nation of Bhutan, located between India and China, is a economically underdeveloped nation. Surprisingly, the country’s lack of money does not translate into misery, though, as they are time and again judged to be among the happiest people in the world by unbiased sources, such as the United Nations. The people of Bhutan are very content, and its a safe bet that the nation’s postal system only adds to their happiness by the fun variety of stamps that they offer.”
Some weird ones include a sweet-and-sour pork scented stamp from China, and burnt-wood stamp (to raise awareness of forest fires) from Brazil.
Stamps of Distinction blog has more on the World’s Smelliest Postage Stamps.