Stephen, our friend Laia and I are heading up to Edinburgh later this month to explore the Edinburgh Festivals. There are seven or so official festivals taking place all at the same time. Each spare space in the city becomes a platform for performances and exhibitions. In fact, there are hundreds of festivals as each venue presents their own selection of international performances.
You can compose an entire blog about the history of the festivals and each year's preparations, performances and controversies. The Scottish Arts Council offers a history of the festivals and a list of their descriptions and dates. I recommend the Fringe Festival's blog.
We'll be there 24-25 August and then back to London on 27 August for the Notting Hill Carnival which is another interesting invent that I have yet to experience.