As you can see, it's a perspective trick which blurs much of the photo and leaves the rest looking like it's a model or miniature. I haven't got £2000 spare for a lens to do it, so I'll settle for a post-production bit of software. It'll be great for my sister's wedding. You need a good wide space, decent light, plenty of action grouped close together, and high contrast, plus a high perspective.
Have a good weekend.