This year Moodscope are partnering with Action for happiness to celebrate the United Nations International Day of Happiness. I hope you'll all join in. Here's what it's all about:

If you ask parents what they want above all for their children, nearly all of them say something like "I just want them to be happy". Happiness is the thing we want the most for the people we love the most.

But the problem is that our happiness has been hijacked. We're bombarded with false images of happiness. Advertisers say it comes from buying their products. Celebrities and the media pretend it comes with fame or beauty. And politicians tell us that nothing matters more than growing the economy.

I could point to many studies confirming how wrong this all is - lasting happiness does not come from what we consume, how we look or how much we earn. But, let's be honest, you knew that already!

Today is the United Nations International Day of Happiness (http://dayofhappiness.net). To celebrate this special day, Action for Happiness (www.actionforhappiness.org) is running a global campaign with support from over 40 organisations and many thousands of people around the world. Their mission is to show the world what happiness really looks like - and in doing so, to reclaim happiness back from the advertisers, celebrities, media and others who try to manipulate us.

Here's how you can get involved...

Step 1: Find. Look through your photos right now for a picture of something that really made you happy.

Step 2: Capture. When something makes you happy today or in the coming days, remember to take a photo of it.

Step 3: Share. Share your images of happiness with others using the #happinessday hashtag (e.g. via Twitter, Instagram, Facebook etc)

People have already shared hundreds of great photos of what makes them happy - and you can see a collection of these on this inspiring wall of happiness (www.dayofhappiness.net/image-wall). Unlike the fake images in adverts and magazines, these authentic photos help to remind us of what really matters. We may not be able to change the world overnight, but together we can share a vision of happiness which is far more real that the one we're sold.

So why not take a moment to find (or take) a picture of something that makes you happy and share it right now. It might be profound, or perhaps profoundly silly! But however small and personal, the fact that you have noticed it makes it quite important enough.

Let's focus on the things that really matter. Let's reclaim happiness.

Mark Williamson

Dr Mark Williamson is director of Action for Happiness, a movement of people taking action to help build happier communities, families, schools and workplaces.