Casey, funny you mention working in retirement. Boomers are giving a whole new meaning to the word. I've received lts of articles through Google about boomers never retiring. Many reasons have been given:

-healthier and want to continue
-retiring and doing something we're passionate about to make a difference
-finances, need the money
-driven by activity
-driven by the feeling of success
-living longer
-witnessed our parents retiring too young