Nice piece on Tom Lehrer, to whom I've been listening a lot lately.
"With audiences nowadays I see it with these late-night [TV show] people, Jay Leno, David Letterman and so on the audience applauds the jokes rather than laughs at them, which is very discouraging.
"Laughter is involuntary. If it's funny you laugh. But you can easily clap just to say [deadpan]: 'A ha, that's funny, I think that's funny.' Sometimes they cut to the audience and you can see they are applauding madly. But they're not laughing."