Check out these lovely images first:
I found these and a link to a tutorial for making a 'bokeh' here, on one of my favorite blogs, Le Fru Fru. It's in Italian (which I'm learning, but not good at ALL yet because I keep knitting instead of doing the Rosetta Stone lessons), but your browser will most likely translate it if needed. The tutorial on Green Laundry is in English though, so that will be helpful :)
A 'bokeh' is "the blur, or the aesthetic quality of the blur, in out-of-focus areas of an image, or "the way the lens renders out-of-focus points of light.(from Wikipedia) In this particular instance, we can create the heart-shaped 'bokeh' through making a lens cover, like this (image from Green Laundry's blog):
I hope you'll go try this out! Again, the link to the tutorial is here. I'm excited to try this and experiment with more night time photography. Have fun and share pictures if you try this out!!