The telethon was held annually on Labor Day weekend beginning
in 1966and raised $2.45 billion for MDA from its inception through
2009.  Jerry Lewis was host along with Ed McMahon. 

The telethon broadcast up to 211⁄2 hours, starting on the Sunday
evening preceding Labor Day and continuing until late Monday
afternoon on the holiday itself.

The MDA stated on August 3, 2011, that Lewis had "completed
his run" as both host and national chairman and that Lewis would
not appear in the 2011 telethon.
(From Wikipedia, the free encyclopedia)