Use prosocial to describe something that benefits other people or society in general. Volunteering at your city's soup kitchen is a great example of a prosocial way to spend your weekend.
The phrase prosocial behavior is used by social scientists to describe what you might think of as simply being a good person. Stopping at stop signs, sharing your cookies with a hungry classmate, giving money to charities, and shoveling your neighbor's driveway in the winter are all examples of prosocial actions. This word was coined to be an antonym for antisocial.