The Twits by Roald Dahl is a very short novel that can be read in less than one hour. Children will enjoy The Twits much more than adults would because of the descriptions and the characters involved; there are humans, monkeys, and birds. The Twits teaches a good lesson that people with nasty, evil thoughts start to look ugly themselves, and if you do something bad to others, the same bad thing may happen to you.
Mr. and Mrs. Twit are old (in their sixties), hideous, and disgusting. Both like to play tricks on each other and do outrageous things. Someone's out to get revenge...
I highly recommend The Twits for children, since they will likely find the story more enjoyable than adults will.