Back in San Francisco I bought two books by guerrilla artist Keri Smith: The Guerilla Art Kit and How to be an Explorer of the World. I showed them to Jaakko and Annika, who promptly went to SF MOMA got the books as well; in fact I think Annika bought half a shelf of stuff there, hopefully reporting her other finds later on.
While How to be an Explorer of the World is very inspirational from the angle of pervasive games changing your perception of the world, The Guerilla Art Kit is definitely my favourite of these. The author goes through numerous ways of making your environment more pleasant and enjoyable through more and less legal methods. Being an outsider to the scene, I enjoyed finding out about ideas such as seed bombs for fire-and-forget AoE guerilla gardening.
One notable thing Smith emphasizes in her book is the temporary nature of her street art. This is both a philosophical standpoint, as life is short in any case, but also a strong practical and legal argument. Temporariness also helps with gaining social acceptability for guerrilla art.
In any case, if you are planning to do street games, check out Smith’s books. At least I found them highly inspirational — even though I don’t plan to cut any stencils anytime soon. Preview her work on her website.