Corrected entry: When Bender shows everyone the card he got for Mom, he opens it and you can hear a melody play before the card says, "I love my mommy". Later, when Fry and Leela are leaving the robot museum, Leela reminds Bender to tell Mom that he loves her. Bender tells her that anyone can say that and that he has something else in store. Bender opens up the card, but this time you don't hear any melody being played. You only hear the card saying, "I love my mommy."
Corrected entry: When the Professor and Mom's clothes are thrown around the bedroom, their teeth are in jars next to the bed (they are definitely theirs as they comment on it on the DVD commentary.) The problem with this is that both of them are "wearing" their teeth, as can be seen when they talk.Dan Moat