Here is a Buffy reference from an older episode of Will and Grace.
Do you know more references?

JACK: So, what is it you do?
MATTHEW: I work in television.
JACK: Oh, my God. I love TV. Buffy is my life.
MATTHEW: Oh.
JACK: I'm so into Willow being a lez. Did you have anything to do with that?
MATTHEW: No, I'm a sports writer. I write news, sports, you know, like that.
WILL: Sports? I got nothing. The last sporting event I watched was "Circus of the Stars."
WOMAN: [TO WILL] Hey, do you have this in a size 8?
WILL: [TO THE WOMAN] I don't work here.
JACK: So, back to Buffy. Is it really--
WILL: Forget Buffy, you boob. Ask him what he does for fun.