Bokeh is a photographic term referring to the appearance of out-of-focus areas in an image produced by a camera lens. Different lens bokeh produces different aesthetic qualities in out-of-focus backgrounds, which are often used to reduce distractions and emphasize the primary subject. (from Wikipedia).
Steps to reproduce this image: wait until it’s dark or almost dark, find some interesting looking lights (e.g. street lights, decoration …), switch your camera and/or lens in manual focus mode, pick a nice big aperture (small f-number) and go wild! 🙂 Make sure to check the result on the LCD of the camera.