Around the holidays you might notice that a lot of photos have a nice twinkly look in which every light looks like a starburst. Photographers achieve this effect with a star filter, but if you don't feel like shelling out the cash for a professional lens filter, you can easily make your own.
Eva Landry demonstrates in this video just how easy it is. She just takes the clear plastic lid off a CD case and scratches a series of parallel lines -- diagonally in both directions and also straight up and down where the diagonal lines intersect. Each intersection is the point of a star, so in this case the effect will create six-pointed stars. Then you just hold it in front of your lens and voila, twinkly holiday lights when you're shooting at night. It's essentially the same as a real star filter -- just rough around the edges.