As evidenced by this Christmas episode (and I've been thinking this since the first episode), y'all can carry a show for 3 hours. In fact some of the best moments are when y'all recap "what everyone has learned" at the end. The guests you've had so far have all been fantastic though.

Guest Ideas:

Pharrell Williams
Donald Glover
D'Angelo (for more than 2 minutes..ha)
Raphael Saddiq
Thundercat
Ghostface Killah
DJ Premier
Sheila E.
Me'Shell Ndegeocello
9th Wonder & Big Pooh (The Little Brother episode)
Nicolay (The Foreign Exchange episode)
Lyor Cohen
Al Green
Jimmy Jam & Terry Lewis
Tina Turner
Clyde Stubblefield