street art/large scale art

I recently watched Banksy's film 'Exit though the gift shop'. I have never been as fussed about Banksy's work aesthetically, as there are a lot of other street artists that I prefer, although I like his work in terms of the impact it has had on the art world, whether it was intentional or not. I went to Berlin a couple of years ago and saw some of the most incredible street art I have ever seen which inspired me to have a go with a friend from home. I would like to explore the idea of working on this scale, perhaps with stencils etc and create something really quite big. I am aware of the legality issues, but I could always work on large pieces of board. As I am going home for two weeks it could be a good brief to do as I will have the luxury of a garden.