Since its grassroots inception in 1970, Earth Day has grown appropriately to international proportions during which an estimated 500 million people worldwide will celebrate their home and resource — planet Earth. It’s nice of us to set aside a commemorative day for the earth, after all, the earth does put up with a lot from us and deserves a bit of a fuss. But once the cake is cut and the party is over, how do we keep the mindfulness momentum? Here are a few extra dates to mark on your calendar to help keep the good times, and the good actions, rolling.

April 24: Arbor Day

Before there was Earth Day, there was Arbor Day: an annual celebration of tree-planting founded in 1872. “The best time to plant a tree is twenty years ago. The second best time is now.”

May 15 (third Friday of May): Bike-to-Work Day

Join the League of American Bicyclists in urging car-bound commuters to bicycle in for a day. Safety in numbers!

June 5: World Environment Day

This year’s World Environment Day theme is Combat Climate Change making it a good day to kick off a large-scale household, community, or civic greening project.

June 8: World Ocean Day

Not everyone lives near the ocean, but for those of us who do, World Ocean Day is as good a day as any to gather garbage from the beach, and maybe have a picnic too.

Sept 21: International Day of Peace

Not only is war hell on the combatants, but it’s hell on the earth too. Give peace a chance!

October 1: World Vegetarian Day

Full disclosure: I’m no longer a full-time vegetarian, but I do know that in broad terms, vegetarianism really does have a lower impact on the environment than a meat-oriented one. And trying it out for one day has a certain exotic flair about it, whether it’s enough to convert you to a full-time regime or not.

November 27, Friday after Thanksgiving: Buy Nothing Day

This classic of anti-consumerism counteracts the popularity of “Black Friday” — one of the busiest shopping days of the year.

December 10: Human Rights Day

Because the earth is more than plants, porpoises and protean depths — it’s people, too.