In 2013, April 25 marks the annual day dedicated to random acts of kindness.

Mark your calendar to change the world, one random act of kindness at a time.

In 2013, Thursday, April 25th is Pay It Forward Day, the annual celebration of the belief that each of us has the power to better someone’s life simply by doing small favors, often anonymously. Picking up the restaurant tab of strangers at the next table, then leaving before they find out. Feeding coins into someone else's parking meter before it expires. Buying gas for your car, and the one next to you at the pump.

The premise — based on the book and movie “Pay It Forward” — is to act without the expectation of being paid back, but with the hope that the recipient pays the favor forward by helping someone else. For the past 10 years, Karma Experiment and the Pay It Forward Foundation have been working to inspire people around the world to engage in quiet, hopeful acts. Many are chronicled on their websites, like a group of third graders in Auburn, New York, including Jerry (“I held the door for a man with a cane”) and Brendon (“I gave an old woman a compliment and told her how pretty she was”).

This year’s goal is 5,000,000 random acts of kindness. What will you do?