DIY Bokeh Filter

So since we put up all of our Christmas lights, I've been playing around with my camera and I made some bokeh filters. They didn't pan out exactly how I wish they had but they still produced some pretty cool photos.
You'll need:
black construction paper
compass or circle template
Start by tracing a circle just slightly larger than your lens. Cut the paper out, leaving a little tab (which will just make it easier to remove the filter from your lens). Fold the circle in half and in half again to find the center and cut out whatever shape you like.

Press the filter into the lens; it should fit snuggly so it won't fall out while you're snapping photos. And then, try it out. Open up your aperture as wide as possible and place lights in the background where they'll be out of focus.
You might need to adjust the placement of the filter and/or the size of the shape you cut out until you get your desired effect.
Here is a side-by-side comparison; the first is no filter.
Good luck!