How the Grinch Stole Christmas (2000)

Revealing mistake: When the mayor has his head shaved by the Grinch, Clint Howard grabs the clippers and shaves his own head down the middle. His hair is yanked off his head before he even moves his hand. Even better in slow motion.

Grinch: Hello!
Grinch's Echo: Hello! Hello! Hello!
Grinch: How are you?
Grinch's Echo: How are you? How are you? How are you?
Grinch: I asked you first.
Grinch's Echo: I asked you first. I asked you first. I asked you first.
Grinch: Oh, that's real mature. Saying exactly what I say.
Grinch's Echo: Exactly what I say. Exactly what I say. Exactly what I say.
Grinch: I'm an idiot.
Grinch's Echo: You're an idiot.
Grinch: [Whispering] All right. Fine. I'm not talking to you anymore. In fact, I'm going to whisper. So that by the time the sound of my voice reverberates off the walls and gets back to me, I won't be able to hear it.
Grinch's Echo: You're an idiot.

Trivia: When the Grinch takes the table cloth from the table, everything on the table was supposed to fall off. When Jim Carrey yanked out the cloth however, everything stayed in place. Jim immediately walked back to the table and improvised knocking everything off and then knocking the table over.

Question: What kind of sleigh did the Grinch build?