Here are some regedit hacks that let you customize the Ribbons screensaver in Vista. To use them start the registry editor (type regedit in the Start search box) and on the left side of the editor navigate to the HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Screensavers\Ribbons section.

Once there, you'll then need to create new values for several settings that can be adjusted. Each new value is created by right-clicking in the right side of the pane and selecting New -> DWORD (32-bit) Value and then entering a name and a value for the value (you'll probably have to double click on the entry to enter the value). The entries that can be created for the Ribbons screensaver are:

NumRibbons => A number which indicates the number of ribbons shown. When entring the value, click Decimal as the base.

RibbonWidth => A number which indicates the width of the ribbongs. Again, when entering the value click Decimal as the base.

Once you make you changes, you need to reboot for the changes to take effect.