Why is Letterman always picking on Singletary?

All you insomniacs, speed freaks and nightwatchmen (some of you might be all three) might have noticed David Letterman's picking on Mike Singletary. Given Letterman's latest ratings, that's probably not many of you.

Every week, Letterman has interrupted his show to conduct a live via satellite interview with San Francisco 49ers coach Mike Singletary about last Sunday's game. A Singletary impersonator appears in a split screen shot in full 49ers regalia and answers questions with the fluidity and grace of Ralphie May in ice skates.

How did this slice of sports satire get started, and how long will it stick around?

It's no secret that the 49ers aren't the hottest team in the NFC. No one knows that little factoid better than Singletary. All his repressed anger reached its peak on Oct. 26, 2008 when an embarrassing loss to the Seattle Seahawks sent Singletary on a post-game press conference tear that could make Jim Mora leap out of his chair and urge him to calm down.

Ever since then, Letterman has been holding interviews with a Singletary stand-in. Letterman asks the questions any well-seasoned sports writer would ask, and Singletary goes off, spouting one to five word phrases that make no sense and rarely follow the subject/predicate form of English we have all come to know and love. In other words, he's every major league coach who ever existed.

The bit has still been going on, and it's not the funniest thing he's ever done, but it has a wicked touch of brilliance to it. The Singletary stand-in's rants are, as one Bay Area sports writer put it, about "everything and nothing" all at once. I'm not saying Letterman's Singletary has the chance to become the new Larry "Bud" Melman, but he's certainly dangerously close to becoming the new "CBS Page Who Thinks He's Batman." In other words, it's vintage Letterman.