Do a small good deed for someone. Tell them to pay it forward. (If you don’t know what that means, it means to do something nice and tell the person you did it for to "pay it forward,“ which means that the recipient of your nice action needs to go and do another nice action for someone and tell that someone to pay it forward, and so on.)
Write about the experience. How did it make you feel? Write a story involving those feelings and explore the idea of what the people ahead of you in the chain will do for others. Think on a grand scale.