Mountain Lion

• OS X Mountain Lion (version 10.8) is the upcoming ninth major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.
• OS X Mountain Lion was announced on February 16, 2012 and is scheduled for a release in the summer of 2012.
• It will gain additional features from iOS, some of which were previously introduced to the Mac in OS X Lion.

Features

• Deeper integration of iCloud, which includes new Open and Save dialog boxes across built-in applications, iWork and third-party applications via an API
• Automatic synchronization of documents in iWork with iCloud
• Time Machine is able to do rotating backups on more than one storage medium
• Gatekeeper – an anti-malware feature based on digital signatures and the Mac App Store
• Reminders – a to-do list application, also on iOS, separated from Calendar

and lot more