I was walking between the two main Framestore offices to pick up my bike at the end of the day and could hear lively brass band music. I turned the corner into Noel Street to find a large group of people with cans of beer following this band around.
It turns out that they are the Hackney Colliery Band who I had heard several times on The Craig Charles Funk and Soul Show (which I highly recommend) on 6 Music. They were launching their album, which came out today, by playing a gig at Phonica Records on Poland Street. I bought the album on the spot and have been listening to it all evening.
I know this kind of stuff happens in other cities too but I seem to stumble upon them more in London.