In the scene where Carrey is in the stretcher at the airport, if you look in the back of the crowd to the right, you will see Fire Marshall Bill from In Living Color. He can be seen when Carrey's ex-wife is speaking to the officer speaking on a walkie-talkie.

Jim Carrey turned down the role of Dr. Evil in Austin Powers so he could do this movie. Submitted by AD

The sound that Jim Carrey's head makes when his head hits the floor in the bathroom scene wasn't added, digitally or otherwise. That is the actual sound of his head hitting the floor.

When Jim Carrey goes to his son's school and reveals that he cannot lie, his son asks him some questions, one being "If I make this face will it get stuck that way?", while of course making a funny face. Then Jim Carrey responds with, "Uh Uh, in fact some people make a good living that way". Do you think the second part of the line is in reference to himself? I think so...