I asked a client to close all open windows and he literally stood up and shut all windows in his apartment. I've had heard that as a bad joke before, but i experienced it live during a support call.
Edit: another highlight was the client who answered the question what 56k modem she used with the words: "My modem is lit up and colorful." This experience probably was the start of making everything glow in RGB as soon as we had blue leds figured out.