Insert disc 4 into the DVD player.
Go to special features.
Go to "Friends of Friends"
Maneuver pointer to highlight the cup of coffee directly below "Guestbook"
Here you will find an egg revealing the shows creators / producers have a cameo in "The One with the Fake Monica" as impatient auditioners. The info is followed by a clip of the cameo (and their sillouhettes are correctly labelled so you know whose back of the head is whose).