"HIMYM" cast delivers fake reveals about series finale on "Letterman"
Teen singer also performs "Tennis Court" and other songs from "Pure Heroine"
Rep. Pelosi offers a cheeky civics lesson on CBS's late-night show
The ABC late night show posts its largest-ever advantage over "Late Show With David Letterman" in key demo
"For the first time in the history of the world more people will die from over-eating than under-eating this year," Bloomberg says
President Barack Obama's sit-down with David Letterman gives "Late Show" its best numbers since Feb. 2010
In leaked video, he also said "SNL" could make him look unpresidential
"Two and a Half Men" stars to read Top Ten list
Attorney for Halderman says all client wanted was book deal.
Read the jokes from tonight's "Jay Leno Show" monologue.
Letterman lands the president for a Monday visit.