Effective Altruism is applying evidence, reason and rationality to the goal of making the world a better place. It is an international movement, that recognises that nearly everyone in wealthy countries have an amazing ability to do good in the world.
Examples of Effective Altruism: giving to the most cost-effective charities, volunteering with the most high impact organisations, thinking critically about what causes to support, consuming ethically, and choosing a career in a way that maximizes impact.
Effective Altruists meet up every month or so to share ideas on ethics, causes, charities, effective actions and career choices. If you are interested in doing good in the world, then come to a meet up and hear the ideas! For an introduction to effective altruism, check out Peter Singer's TED talk.