Buy a bunch of flowers and give them to the first person you see who looks like they need them.
Awaken the child in adults, or bring joy to children themselves, by leaving pots of bubbles on park benches. Who doesn't like bubbles?
Take photos of things you think others would like and send them on so they know you are thinking of them.
Take part in community activities to get to know the people in your neighbourhood and build community spirit. If you are feeling adventurous organise a street party - such a great way to do something for many people at the same time, include isolated neighbours, introduce people and create a happy community environment.
It's fun to splash in puddles but try not to splash others, especially pedestrians when you are driving.