With the latest version 2010, the Ribbon interface came to SharePoint users. Microsoft learned a lot since introducing that kind of user interface to us in Office 2007 and the Ribbons are well built now.
Since many organizations have their own set of rules, links, connections people are used to, many will want to customize the ribbon. André Lage an MVP from Portugal working in Switzerland at the moment has posted some hints. He also refers to Microsoft’s example.
Additional reading:
Jonathon Frost: Adding Custom Button to the SharePoint 2010 Ribbon
Microsoft’s SharePoint Developer Center: Module 10: Creating Dialogs and Ribbon Controls for SharePoint 2010
MSDN article: Architecture of the Server Ribbon
How to Add a Tab to the Ribbon in SharePoint Foundation
MSDN article: Customizing the Server Ribbon
MSDN article: Building Block: Server Ribbon
