Mac OS X Mountain Lion has 43 secret desktop wallpapers hidden in one of its folders. They are all beautiful, high quality and this is how you find them.
Mac OS X Moutain Lion and its Safari web browser sharing options allow you to share and send any web page vie email as a PDF attachment in a matter of two clicks.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.