One of the most obvious features of the Project 2010 client is the introduction of the ribbon. The ribbon first appeared in Office 2007 and made it into most of the client application except Project. The idea behind the ribbon is that it surfaced commands and features that had previously been nested away under several menu options.
In Project 2010, the ribbon has finally made it into the product. It consists of four main tabs (Task, Resource, Project and View) and a couple of contextual tabs that are shown depending on what tab you select.