At the time of this writing I'm a bit confused because the version I saw gave the "hand" story first followed by the "teeth" story, but comments here and on Amazon say the movie presents the two stories the other way around. And it should be noted that I haven't read the original stories; I judge the movie as a stand-alone form of entertainment.
So, imagine what would happen if your hands stopped responding to commands from your brain and began doing whatever *they* wanted to do. And what if your hands plotted a revolution requiring an army of hands from other people. If you happened to see the modern "Addams Family" remake then you can extrapolate: picture a bunch of "Thing" hands running around free. I thought the army, and how they got that way, were very funny. OK, there is a rather serious horror story going on in the background, and Matt Frewer does some excellent hand-acting.
As for the second story, well, I can't say much without giving too much away. But I was blown away by my favorite character, the wind-up teeth. I have a small collection of similar wind-ups, similar in that they walk or play instruments, but I never saw anything like these teeth. I felt totally torn between the seriousness of a hitchhiker-horror story and the humor of a wind-up character. Enjoy, just for fun.