Often the songs on my iPod activate memories, long streams of recollection that cascade through my mind until my morning walk is over. At times I get so lost in thought I can' t remember covering parts of my route. My body handles the navigation while my mind is busy elsewhere . With the iPod on shuffle , I never know w what song will trigger the internal time machine and send me tumbling into the past. It could be Frank Sinatra or Frank Zappa, John Hiatt or Elton John. The music plays and the movie of my life unspools. I find it all very entertaining. Maybe you will, too .