It's the Blue Cross Take Your Dog To Work Day on 14th September.

I don't know how much money it raises, but as a marketing and PR exercise to promote dog ownership, the day is almost without rival. It always gets plenty of media coverage. It's got strong celebridee endorsement. And getting pet owners to bring their dogs into work is a very clever way of getting more people thinking about getting a dog.

See http://www.takeyourdogtoworkday.org.uk/ for more (if you're interested, there's a downloadable poster you can display in the practice).