My friend Phish wrote up this list of natural mosquito remedies. It's a great list, and if it helps even one person not get bitten this summer, it was worth posting!
1. The blades of a spinning fan is the best way to kill mosquitos. Mosquitos can only fly in still air, and they do this mostly over stagnant water. The wind current of a running fan disturbs them immensely. They will try to fly behind the blades for stability and wind up flying into them and getting chopped to pieces in the meantime. Poor mosquitos! The ones that manage to escape will leave you alone as long as you have an artificial wind source as your plan of attack.
2 (aff). Lemons Most people believe in the power of citronella. And those people will swear by it's effectiveness. But lemons are much more pleasant smell to us and do a great job of keeping the mosquitos at bay. Cut about a dozen fresh lemons in half and place them on your window sills. You can also use lemon grass. The smell will drive away most of the mosquitos. Use your fan as a back-up and you should be enjoying a bite-free summer.
3 (aff). Eucalyptus oil and Deet are both great mosquito repellents. And do you know which common cold remedy product has eucalyptus in it? Vicks ® vapor rub. Apply it to your upper body (chest, back, arms), and if you are wearing shorts, get your legs, too. You can also find chemical free Deet (check your natural or health food markets) which you can apply to your skin and clothing. That should keep the little blood-suckers at bay.
4. A mosquito net (kind of idiot-proof, right?) A mosquito net won't kill the little suckers, but a good one will certainly keep them away from you. If you have an outdoor gazebo or tent that you enjoy hanging out under on a nice summer's night, put a net up all around it for a bug-free atmosphere. A pretty net around your bed can serve the dual purpose of making your room look like a Casablancan get-a-way and keeping you out of harms way of being bitten while you sleep.
5. Vitamin B1 Every year, I forget about this vitamin trick. I had heard for years that you had to start taking it weeks before summer for it to be effective. Then I always forgot which B vitamin it was. And now I know for sure. Vitamin B1 does the trick! Taking this supplement during the summer months makes you a lot less tasty to the little vampires. Depending on what you eat, this method is about 50% effective. Some people swear by garlic, too. I'll just keep eating pizza!