In July 2012, the United Nations General Assembly adopted Resolution 66/281 which decreed that International Day of Happiness would be observed every year on 20 March. The stated aim of the Day is: "To promote happiness as a universal goal and aspiration in the lives of human beings around the world". Further background can be found on the UN International Day of Happiness web page.
One of the main organisations promoting the Day is Action for Happiness. They say "People are now recognising that 'progress' should be about increasing human happiness and wellbeing, not just growing the economy at all costs". They have set up a website with inspirational ideas for things you can do on the day at http://dayofhappiness.net. You can also find lots of resources and downloads on the Action for Happiness website.
Another useful website for older students is the Happy Planet Index which is a 'global measure of sustainable well-being' developed by nef - the new economics foundation. It ranks countries based on rank countries based on "how many long and happy lives each produces per unit of environmental output".