With an election year looming, the venerable late-night sketch comedy series takes plenty of jabs at the political scene, even including a pair of party heavyweights -- John McCain and Al Gore -- as hosts. Audience favorite Christopher Walken, Bernie Mack and "SNL" alum Dan Aykroyd are among the other celebrity hosts to join a regular cast of players that includes Tina Fey, Jimmy Fallon and Tracy Morgan (in his final season).