I'm kind of a control freak. I always want to know who wants to use my devices and why. When I do let people use my devices, I sometimes say, "OK, but you have x minutes and you have to give it back when I say so; no 'buts.'" Having said that, can anyone recommend an app I can install on my Mac that will notify me whenever someone, other than myself, uses it? Some information that would help me figure out what they're doing would be a bonus, but I can always get that info by contacting whoever's using my Mac.