You knew David Letterman would have some great guests help to send him off as he winds down a memorable career on late night. Not surprisingly, the great Norm Macdonald is hilarious in his final Letterman appearance, but it is a bit surprising to see crusty Norm get so emotional. This one is worth watching . . .

You can follow Norm on Twitter here.

While you’re laughing your ass off watching this video, perhaps you’ll get motivated to hit the gym as well . . .

Christina Aguilera found herself playing the Wheel of Musical Impressions on The Tonight Show with Jimmy Fallon. Both of them were pretty impressive with their impressions but Christina stole the show with an epic imitation of Britney Spears singing “This Little Piggy.”

Here’s Frank Caliendo at his best with a parade of characters helping him mock the over-the-top Richard Sherman coverage.

This video is absolutely hilarious. You can’t stop watching as more people face the child ghost in the elevator.