One of the best reasons to watch late-night TV occurs tonight, as The Late Show with David Letterman welcomes an annual guest, comedian Jay Thomas, who sits down with Dave to tell his terrific “Lone Ranger” anecdote (what? you mean you’ve never heard it?) and then knocks a pizza off the top of a Christmas tree set up in the studio–with a football (Dave takes his jacket off and joins in. If you want to see a riotous example from an earlier year, click here.) Also, singer Darlene Love belts through her classic, ’60s-girl-group, always-brings-the-house-down performance of “Christmas (Baby Please Come Home).” And as if that wasn’t enough, tonight’s third guest is Mickey Rourke, fresh from his comeback in “The Wrestler” and always a completely unpredictable talk-show guest. Do I have to program your DVR for you???