Today, Apple puts a little more "Rawwwrr!" in your unibody aluminum'd awesomeness! Mountain Lion, the latest version of Apple's OSX is available for download directly from the Mac App Store.
What can you expect from Mountain Lion? Apple says there are 200 new features in this release, many of them meant to help unify the user experience across devices and bring your laptop into parity with your smartphone's user experience. That means greater iCloud integration, iMessage and the introduction of an iPhone/iPad like Notification interface. Here are some of the other features Apple says you can look forward to in Mountain Lion:
Tighter Facebook and Twitter integration across apps, dictation which allows you to talk anywhere you can type, better content sharing integration in Safari, Airplay Mirroring, Game Center integration, Power Nap which updates certain apps even when your laptop is sleeping, and much more. For the full list of what's new in Mountain Lion, you can click here.
There's also a great website here, called "Roaring Apps," which shows you all of the apps which are and are not compatible with Mountain Lion. I'd advise you to look there before upgrading if you use a few older apps and rely on them.
For the full list of what you need to know before upgrading to Mountain Lion, including if your Mac itself is compatible with the upgrade, look here.
To find out if you're eligible for the free upgrade to Mountain Lion through Apple's "Up To Date" program, make the jump to this link.