One of OS X Mountain Lion's lesser-known features is the curiously named Power Nap. It's roughly analogous to that sleeping mountain lion you see at the top of this post; while he's catching some z's in the tree, his brain is constantly aware of what's going on around him, monitoring sounds and scents that might spell danger or food.
Likewise, Mountain Lion Power Nap will wake up just enough of the system on certain Macs to grab email, notes, reminders and messages, run backups, and download OS X updates. All of this i
