These are shapes of light in the blurred background of photos. Interesting shapes can be achieved by using a bokeh filter over the camera lens. Bokeh is a photography term derived from the Japanese word for blurred.
The Bokeh Filter is a simple filter that clips onto the end of your lens. This filter blocks out pieces of light that cause the bokeh (blur) in your images to take the shape of the filter. Cool stuff and they cost only ten dollars.