You've probably seen plastic bags filled with water suspended from string at some point in your life, on a patio or outdoor seating area at a restaurant. The movement and amplified color produced from the refraction of light on the water proves to be a potent pest deterrent, ushering away flies and some stinging insects.
The Anti-Fly Sphere by José de la O is a more elegant approach to the plastic bag, and certainly a greener approach to bug spray. The Anti-Fly is comprised of a glass bulb and stopper and utilizes the same concept as the bag-full-of-water in a more elegant form.
While it's just a concept for now, the idea is solid and something that should be readily recreated.
Maxwell & Ursula's Light Rental Reno: The Cabinets
Juan's Garage Turned Modern Guest House
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Commercial Flour Sa...
10 Picnic-Ready Salads to Eat Outside
Recipe: Thai Ginger Chicken Stir-Fry
I've seen the hanging plastic bag trick all over New Mexico and it works, but yeah, it looks pretty trashy. This is so much nicer! I wonder if the flies also dislike hanging crystals???
I wonder if you could make your own version out of recycled incandescent light globes?
BakedandBloom I thought the exact same thing!! And I believe we could do it, it would just have to be clear glass...I don't think this trick would work with the frosted glass ones. I think I'm going to log off and go collect some!
lindsclou, let us know how it goes. It was my first thought as well.
I thought the same too, but just a regular bulb. I didn't think about a larger size. I've never seen the bag "trick" but now I'm really curious.
There are some vases that are round at the bottom but have a stand to accommodate them. I imagine that would to the trick also. I may now have an excuse to purchase the artsy addition.
You could probably use a boiling flask: http://amzn.com/B001VDS5C0