The Hills' promotional juggernaut rampages on (and on). The show's star, Lauren Conrad, was on Letterman last night, and all Dave cared about was Lauren's former friend, and current melodist, Heidi Montag. "Are you friends?" he asked the wispy, vaguely sad fashion designer. Of course her reply was no, so he suggested that perhaps they are "frenemies." David Letterman knows what "frenemies" are! I barely know! He must watch a lot of Sex and the City. He continued on to ask about Heidi's Silly Putty-crafted boyfriend Spencer, who he calls a "newt." Lauren, an amateur zoologist, asks "Isn't that a reptile?" and the world falls apart a little bit more. Click for video.