Basically you make a toy then release it into the wild! Each one has a tag on it explaining that it really is for you to take home, and invites finders to log their find on the toy society blog.
You can see the blog here, and photos of all 191 drops so far around the world!
I decided to let the little yellow monster free, and made up a tag and envelope from brown paper and pages from 'The Jungle Book'.
At first I wanted to leave him in the playground in my favourite park, and I tried to get up early so I could leave him inconspicuously, but alas, there were people and prams and kidlets everywhere. Plan B was a little park near my house enclosed by tall hedges and a squeaky gate. It was deserted on a cloudy morning and success!
Here he is, waiting patiently on the swing to be found.
It felt a little strange leaving him there and walking away, guess you get a little attached to the things you make. I do hope he's OK (and it doesn't rain!)