Here's a good 18 minute TED talk that will brighten your day.
http://www.ted.com/talks/nic_marks_the_happy_planet_index.html (http://www.ted.com/talks/nic_marks_the_happy_planet_index.html)
And this... a more physical way of getting you blood moving. You will be amazed by these girls. Keep watching as they just keep inventing things to do with a jump rope. (As far as I can tell this is all one take - unedited!)
http://blip.tv/play/Ae+9MJOSSA (http://blip.tv/play/Ae+9MJOSSA)