Here's the whole show. You'll have to put up with a commercial, and then what I'm talking about happens is the first thing after the intro music, 20 seconds in.
"Hey, everybody," Jon Stewart yells in his usual way, trying to get people stoked for the show. "Welcome to 'The Daily Show,' my name is Jon Stewart. We got a good one for you tonight. On our program, uh..." He looks comically at his notes as if maybe he forgot he has the President of the United States on his show. He continues, using a rising inflection obviously intended to evoke a strong response from the audience: "this evening, tonight, the President of the United States Barack Obama..." Nothing. Cheers were intended there. Stewart elongates the sentence with material that I think was either improvised or intended to be muttered overwhelmed by rapturous noise from the audience: "... will be joining us on the program tonight." And then a joke: "He's the star of the new film 'Here Comes the Boom.'" And that gets a laugh, a small laugh, which is interesting because of the way it points up the contrast to the utter absence of reaction to the news that the President was on the show.
This audience — presumably, the key demographic of young adults who went mad for the man last time — is not excited at all.
ADDED: It's "Here Comes the Boom," not "Here Comes the Boo," as I thought I heard, transcribing. I pictured something for Halloween, but it turns out: "A high school biology teacher looks to become a successful mixed-martial arts fighter in an effort to raise money to prevent extra-curricular activities from being axed at his cash-strapped school."