PBS will be airing a two-hour-long documentary based on Michael Pollan's excellent The Botany of Desire (previously recommended here).
The tulip, by gratifying our desire for a certain kind of beauty, has gotten us to take it from its origins in Central Asia and disperse it around the world. Marijuana, by gratifying our desire to change consciousness, has gotten people to risk their lives, their freedom, in order to grow more of it and plant more of it. The potato, by gratifying our desire for control, control over nature so that we can feed ourselves has gotten itself out of South America and expanded its range far beyond where it was 500 years ago. And the apple, by gratifying our desire for sweetness begins in the forests of Kazakhstan and is now the universal fruit. These are great winners in the dance of domestication.
A five minute preview of the show is available on YouTube:
I've watched the whole program and it's a worthy companion to the book.
Update: PBS has put the whole thing online for free. (via unlikely words)