Apple are soon to release a major update to MAC OS with the release of Mac OS Mountain Lion. Building on what now must be declared as a success iCloud is to be heavily integrated into the OS with new additions including:
Reminders – in an App style structure providing synchronized reminders on all your iOS devices.
Notes – the same look and feel as the iPad variant Notes will allow for simple yet not too basic note taking in a synced environment.
Game Center – surprising but perhaps not considering the hack that iOS had made into the mobile game arena Game Center will bring on-line gaming to one neat interface.
Messages – combining iMessages and iChat to one application.
Other new features will be deeper integration with Twitter and AirPlay mirroring.
There is a beta version of Messages available from via Apple directly here.
And to read more check out this page from Apple Mountain Lion is expected to land this summer.
For a full family tree of Apple OS from the Lisa all the way to the present you may like to visit this Wiki.
Image is from the nice folks here.