Isn’t Power Nap an awesome new feature of OS X? It is if you’re a Mac user but to Windows users, it’s old news. If you missed the news, Power Nap allows your Mac to keep up to date while in sleep mode. So emails are updated, things get synced to iCloud, system updates are pushed through and even TimeMachine backups are performed in a silent and power efficient manner.
(We’d be remiss in not acknowledging the fact that some of this comes directly from iOS 5, too.)