(Manchester) Urban Sketchers
Urban Sketchers originated in Seattle in 2007, with the following manifesto:

We draw on location, indoors or out, capturing what we see from direct observation.
Our drawings tell the story of our surroundings, the places we live and where we travel.
Our drawings are a record of time and place.
We are truthful to the scenes we witness.
We use any kind of media and cherish our individual styles.
We support each other and draw together.
We share our drawings online.
We show the world, one drawing at a time.

Of course urban sketching, and sketchers, have been around for a while; as the sketchbook drawings of Turner and Girtin testify.

Manchester Urban Sketchers is a forum for posting and commenting on sketches made at their meets around the city and its periphery.