These are some interesting things about the musical. I've gotten a lot of these from my ballet teacher, who was in Cats. If you have any, please send them to me! I will be sure to link you.

1. There are four regular people behind the set singing, just to balance out the vocals.
2. The orchestra is set up behind the set.
3. Four cats don't have microphones- Tumblebrutus and Pouncival, because of all the flips, Victoria, because she's all white, and the mic would show, and Macavity...for obvious reasons.
4. The microphone packs are inside the unitard on either the left or right shoulder/chest area, and the actual microphone is in the wig.
5. The same actor who plays Plato, plays Macavity in the US productions, and the video. In London, he is played by Admetus.
6. The same actor who plays Ademetus plays the Rumpus Cat on the video. In London, George originally played him, but the actor who played George left after 19 years, so they made Alonzo the Rumpus Cat. Alonzo also plays Rumpus in the US Tours.
7. Grizabella (in a different outfit or course) is in Jellicle Songs For Jellicle Cats, as well as the Tugger. He wear his black unitard, just without such a big wig and the shoulder thing.
8. The wigs are made out of yak hair.
9. The makeup takes about 45 minutes to do. You have to put a layer of powder on after each layer of makeup, or else you'll spend intermission putting your makeup back on.
10. Yes, the actors have to do their own makeup.
11. In London, there was a Carbucketty and a bill Bailey. There was a Tumblebrutus in OLC Growltiger's Last Stand. In OBC there was a Pouncival and a Carbucketty.
12. The actors have to keep their thumbs tucked in, because cats don't have thumbs.
13. You will never hear a cat in the show meow. Think about it. That just wouldn't sound right.
14. Cats moods change very often. They go from mean to playful just like that.
15. There are 23 sections, I believe, in the Jellicle Ball. Gillian Lynn named each section differently. For example, Warshaw is the ending of the Jellicle Ball. Princess Louise is the part where only some of the cats dance, the part right before the ending. Gillian Lynne got this name because she was smoking at a pub near the theatre when she came up with this cheoreography.
16. The license plat on the car either says "TSE 1" for, of course, T. S. Eliot, or "NAP 4", for John Napier. The numbers get higher for each production.
17. There are three "hench cats" for Macavity. In the video, it's Mr. Mistoffelees, Coricopat, and Admetus. Other productions vary. In London, it's Carbucketty and Coricopat. In the UK tours, I know that Coricopat was one of them.
18. Marlene Danielle (Swing, Demeter, Bombalurina) and Susan Powers (Chorus) were both part of the cast for the entire run on Broadway.
19. On Broadway, Mungojerrie and Rumpelteazer were originally played by Etcetera and Coricopat. The song about them was narrated by Mister Mistoffelees as they danced about. It was sung to entertain Bustopher Jones.
20. The Broadway show featured "In Una Tepida Notte" in place of "The Ballad of Billy M'Caw" as the duet sung by Growltiger and Griddlebone during "Growltiger's Last Stand."
21. There were eight acrobats in the Original Broadway version of the show, instead of two like the Original London version.
22. The Old Gumbie Cat trio for the chorus was originally Cassandra, Bombalurina, and Jellylorum.
23. Many predicted that the show would be a failure, and it almost was. A bomb threat during the very first performance caused the theatre to be evacuated while the cast were still in their costumes.
24. The original version of "Mungojerrie and Rumpelteazer" from London was quite different from the one featured in the video and other productions worldwide. It was slower, jazzier, and sounded a lot older than it was. The London production was also the only production to feature "The Ballad of Billy M'Caw," which was cut from the Broadway production and excluded from other productions (Replaced by "In Una Tepida Notte" from Madame Butterfly), against composer Andrew Lloyd Webber's wishes.
25. Also, Pouncival was nonexistent, his name was Carbucketty instead. A character known as Jemima existed in the London production, although some alterations were made (including a name change) when she was brought to Broadway.
25. By the time the Broadway production opened, (a bit more than a year later) the London dancers were wearing through the set, so it had to be replaced in plastic, rather than the papery-substance it was originally done in.
26. The original set was not the only thing to be replaced. Shortly after the opening of the Broadway production, the costumes were changed. Bombalurina (who had originally looked like Broadway Bombalurina) was given the orangey-red coat we see her with today, and Demeter (who looked like a golden version of Bombalurina) was given her current coat. Rumpelteazer and Victoria did not wear wigs at all, but had their hair styled like cats' ears. However, in 1983, when Etcetera became a separate character, both she and Rumpelteazer got wigs.
27. CATS won 7 Tony Awards.
28. There are over 2,500 huge props used.
29. The Broadway production of CATS has used more than 59,705 condoms to protect body mikes, 119,248 large cotton balls, 7,451 yards of gaffer's tape, 28,976 wig caps, 2,633 pounds of hair pins, 627,628 fluid ounces of biodegradable laundry soap, 5,158 g-strings and Fanni-Panties, 7,142 knee pads and 278 gallons of make-up remover and removed 237 pounds of chewing gum from bottoms of seats and displayed 34,340 subway posters.
30. In the beginning, Sillabub only sang one solo- The Moments of Happiness. Memory was sang by Grizabella, Victoria, and Tantomile.
31. Originally in London, George, Munkustrap, and Quaxo sang Old Deutoronomy. Quaxo also sang the male part of The Gumbie Cat, which had three verses instead of two.
32. In Finland, the cats wear no shoes. They also have very odd costumes, blue, pink, and green kittens.
33. Finnish Cats takes place in an old building, not a junkyard.
34. In Finland, Quaxo and Mistoffelees are two different characters. Quaxo and Coricopat are girls.
35. The combined weight of the whole gumbie suit weighs around 70 pounds.