Mosquitoes. They can instantly ruin a good summer picnic, outdoor adventure or night with the windows open.
Not only can a mosquito bite swell up and itch like crazy, keeping them away isn't pleasant either. There are sticky bug sprays, smelly candles, and even after all that, you still get bit!
Instead of messing with smelly solutions, try the Anti Mosquito - Sonic Repeller app. I know what you're thinking - "How can an app possibly keep bugs from biting me?"
The app plays a unique, high-frequency sound that supposedly keeps mosquitoes and other bugs away. The human ear can't hear that frequency, so it won't bother you.
The app's designers admit that it's not 100% effective. They say that there are 3,500 known species of mosquitoes and not all are repelled by the same frequencies of sound.
I wasn't able to find any scientific research supporting the idea of sound as a mosquito repellent, and we don't have many mosquitoes here in Phoenix - one of the few good things about the insane heat - so I wasn't able to test it out myself.
Still, the app is free, so download it for yourself and give it a go. Then, let me know in the comments below if it worked for you.
Update: This morning, the Android link for this app was taken down. If you want to try an Android mosquito repellent, I've linked to Anti Mosquito HD.