I can't say enough good things about this "movie." It consists of a number of short cartoons, and there are several additional undeveloped shorts in the bonus material at the end which are almost as fun (my daughter enjoys those storyboard rough ideas almost as much as the fully animated cartoons -- which may indicate that all the money spent on the amazing CG animation might be a complete waste!). Mater is the central character in each story, in a tall tale told to Lightning McQueen, each of which typically ends with a surprise hint that, just maybe, they might actually somehow be true. Pacing and humor are spot on throughout. This is even funnier for adults than for kids, with lots of allusions, references, and situations which the kids won't get but will make you laugh out loud. The music complements the film perfectly.
My daughter watches these over and over, and it's always a good option when we've offered to give her just 10 minutes of video time, since the stories are all short and self-contained. I highly recommend this for both adults and parents of small children.