Most people would say the best way to teach your child to have responsibility is to have a pet. OK this is good too. But what happens is that after a while, the novelty wears off and your child forgets to feed or clean the pet. Then the responsibility falls on you, the parent.
We have lots of pets over the years and still do: cats, guinea pigs, chickens, fish and rabbits. Pets are really great for children. There's no denying that but I've found something better to teach children responsibility.