Maura Tierney does not appear in this episode because she was busy filming the movie "Liar Liar."
The "Hello Sam"/"Hello Ralph" gag is a referral to the Looney Tunes characters of Sam Sheepdog and Ralph Wolf. They are considered spin-offs of Wile E Coyote and Road Runner, also Looney Tunes characters.
Is the only episode throughout the series where Maura Tierney (Lisa Miller) is absent.