I just finished watching Real Time with Bill Maher this evening, on which evolutionary biologist Richard Dawkins was a guest. While Real Time is a show primarily revolving around politics, Dawkins answered some questions regarding evolution and cited an interesting example of rapid evolution from his new book The Greatest Show on Earth.
In his book, Dawkins talks about the rapid evolution of a species of lizard called the Podarcis Sicula that was observed over a few short decades. I did a little bit more research on this on my own, and the results were quite interesting. 5 male and 5 female lizards from the island of Pod Kopiste were relocated to an island 4.2km away called Pod Mrcaru. Over a period of approximately 4 decades, these lizards and their offspring were observed. The results of the experimental relocation showed changes in head morphology, bite strength, and digestive tract structure during this period of time.
Researchers also noted that the abundance of food on Pod Mrcaru also caused decreases in hind limb length as a result of a passive, grazing food gathering style that they were able to adopt versus the more aggressive, hunter-gatherer style required in Pod Kopiste.
For those that are interested, there is a longer article on this study at http://www.scitechexplained.com/2010/02/evidence-for-evolution-lizards-from-pod-mrcaru/. Dawkins appeared on Real Time with Bill Maher on October 8, 2010, if anyone wants to check that out as well. There is also a related article on some lizards in New South Wales, Australia that are currently making the transition from eggs to live births. Read it at http://news.nationalgeographic.co.uk/news/2010/09/100901-science-animals-evolution-australia-lizard-skink-live-birth-eggs