From The Thomas Pynchon Joke Book, ed. Deleuze and Guattari (Turner Classics, 1998):
[Sound of toilet flushing.]
Q: In the famous CNN peek-a-boo sequence, which one was the real Pynchon?
A: The old guy in the "I Won the Pulitzer" T-shirt.
Q: How do you know you've just met Thomas Pynchon in a bar?
A: Because you're still John Laroquette but all of a sudden everyone takes you seriously.