A few months ago, a friend moved into a ground-level studio apartment that had a window in the kitchen that faced out to a somewhat busy street with a lot of foot traffic. After the first few mornings of waking up to the dulcet sounds of someone rifling through her recycling bin outside her window, she decided to add another layer of privacy in addition to curtains: plywood.
Bluntly put, her initial solution didn't do her place any favors: not only did it make her building look abandoned, it also blocked a lot of the sunlight coming into her studio. Then, after seeing this idea of using laser cut plywood placemats in Living Etc, she found some faux wood-grain placemats that had a lacy pattern cut around the edges at the World Market. Using fishing line, she stitched the panels together to cover the lower half of the window and hung it from two hooks. The placemats are thin enough so that light can come through, and the lacy pattern keeps this particular barricade from seeming too obtrusive.
[ Photo from Living Etc., placemats shown in photo are from Hygge ]