On tonight's 30 Rock, a fake rumor that Liz was pregnant started circulating. (In reality, though, she was just covering for Avery, who needed to secure a promotion.) How'd everyone find out? Why, from Nightly News' Brian Williams, of course!

Brian Williams Makes the Best Cameo Ever on 30 Rock
Brian Williams Makes Another Amazing 30 Rock Cameo

Update: Another moment, from the end of the episode!

[30 Rock]