I spent some time today searching through the Mac App Store for an app that would monitor the battery status of my keyboard, mouse, and trackpad and put them in my notification center. I was unsuccessful (development opportunity!) but while searching, I did stumble upon Boss Radar. Boss Radar will monitor the bluetooth signal of any device it sees and let you know when that device is close. It could, for instance, watch out for your boss's cell phone bluetooth signal. When the device gets close, Boss Radar, will do things like change wallpaper, stop music, open up documents, and change browser pages. As the developer explains, it will make it appear as if you have "god-like focus". I didn't download Boss Radar and I really don't have any need for it but the fact that: a) a Mac developer thought of it, and b) a Mac developer actually built it and now sells it for three bucks explains exactly why I love Mac developers.