Fred Armisen Does Ira Glass Impression On Un-Aired 'SNL' Dress Rehearsal

This weekend, Fred Armisen will co-host a special episode of This American Life with Ira Glass called "Doppelgängers." Armisen's amazing impression of Glass has never actually made it onto SNL, but he did do it alongside Seth Meyers on Weekend Update in this un-aired dress rehearsal segment.

JIMMY FALLON: Tracy Morgan Sings 'Goodbye' To '30 Rock' Cast, Boyz-II-Men-Style

When Tracy Morgan sings Boyz-II-Men's "It's So Hard To Say Goodbye to Yesterday" to his 30 Rock co-stars on Late Night with Jimmy Fallon, Alec Baldwin visibly tears up.