Let's hear it for 5!
The 5th episode of The Muppet Show not only featured Rita Moreno, who won an Emmy for her appearance,
but it featured the first appearance of Veterinarians' Hospital!
The 5th episode of The Muppets featured a battle between Reese Witherspoon and Miss Piggy:
And Fozzie's girlfriend serenading him with "True Colors":
Depending on what order you look look at, the 5th episode of Muppets Tonight also featured a female guest star, Cindy Crawford, and one of my personal favorite Muppets scenes of all time (7:03 mark):
5. That's that number of the day! Ha ha ha!!!