I'm guessing that everyone's already seen the Jimmy Fallon video where they make news anchor Brian Williams rap along to Rapper's Delight:

https://www.youtube.com/watch?v=-YCeIgt7hMs

Well, the other day they did Gin and Juice: https://www.youtube.com/watch?v=jidziKYG9jk

And then yesterday Williams was interviewed on the show, and was brilliant:
https://www.youtube.com/watch?v=zDyt0M8Zecw
https://www.youtube.com/watch?v=Z8EKjgU5Lts