The Ribbon for WinForms project is a managed wrapper around Microsoft Windows Ribbon Framework (first introduced in Windows 7 and now available also in Vista).
As such, it has the same limitation as the wrapee. Specifically, dynamic changes at run-time are quite limited.
What you can do is:
1. Use application modes, which allows you to set several modes in the application, where each mode has a different set of tabs/groups/buttons.
Note that you can change the UI at runtime but only to predefined UI.
this post for more information on application modes.
2. Use contextual tabs, which are additonal tabs that appear when you set a "context".
Again, allows changing at runtime, but should be predefined.
this post for more information on contextual tabs.
The only feature where you can add UI is using