The word of the day recently in Visual Thesaurus was Spavined: "When horses get long in tooth they also tend to get spavined -- that is, unable to walk because of leg swelling. The word goes way back in English (15th century) but is ultimately from French. By extension, it can mean 'old, decrepit, over-the-hill.' "
To keep from getting spavined I'm brain dancing (www.creative dance.org/about braindance.cfm), reading about the brain: The Female Brain by Louann Brizendine and the Seven Deadly Sins of Memory by Daniel Schacter, and getting lots of aerobic excercise (NPR interview with Martha Weinman Lear, Plumbing the Forgetful Mind (Feb. 14, 2008) mentions research showing it helps with speed in cognitive processes even more than other kinds of toning excercise). Also, trying to pay attention by "practicing" mindfulness and meditating. Social connections and meaningful work are key: Encore, Finding Work That matters in the Second Half of Life by Marc Freedman is a fun read about what individuals have chosen for mid life career changes.
I recently heard Van Cliburn speaking on Morning Edition on NPR said, There's enough music for a lifetime, but not enough lifetime for all the music." so thats the other pursuit that is so endlessly fulfilling and energizing. Life is too short. yippeee!