I have worked with yarnbombing projects in the past. The largest was in my hometown Turku last year. You can see photos of the Knit 'n' Tag-project here.
Now there is a new project I'm taking part in. It is tied to a charity project of getting people to knit hats for a prem baby unit. A petrol station + restaurant complex near Tampere, Finland will be covered with lots of graffiti inside and out. I'm involved in coordinating some of it through a Facebook group. There will also be school children taking part as part of their craft learning.
I have made a few pieces now, mainly crochet.
Hope to get many more made before it will all go up on the 15th of September!