another question in a bottle

I don't watch the late-night talk shows anymore, but I was just walking by a TV tuned to one. When did David Letterman get the gap between his front teeth fixed? It must have been recently, judging by how he kept licking them.

(By the way, Steve Martin is really starting to look old, but he still moves like a classical dancer. I thank the charity of fate for every classic movie Martin doesn't help remake -- but if there's anyone who deserves Jacques Tati's mantle, it's Steve Martin.)