You could do this using AutoText (Building Blocks) and assign a keyboard shortcut to your shapes. I was hoping someone else would answer this one because it is not simple.

First I would download the Building Blocks Enhanced Tools from Greg Maxey's site. It replaces the Quick Parts button on the Insert Tab with an expanded Document Parts button. One of the choices is AutoText. This is the easiest way to work with AutoText in Word 2007.

Select a shape and add it to AutoText. You need to give it a unique name. Then do this for each of your shapes. Store them in a separate template, not the default. You will be using this template to distribute the AutoText and keyboard shortcuts to others. The separate template can be a dotx template, no macros are involved.

Then find you quick action toolbar's drop down at the end. Select More Commands. On that dialog box click on the button to customize keyboard shortcuts.

A dialog box will pop up to customize keyboard shortcuts. The first thing is to change the location for storage from normal.dotm to your template. Then under Categories on the left, pick AutoText. Find one of your AutoText entries in the selection box on the right. Click in the window to assign a new shortcut key.

I would recommend holding down the Alt key and pressing the letter S, then release them and press the number 1. It will show up as "Alt+S,1." Click on the Assign button.

For your second shape use 2 instead. I am assuming you have fewer than 10 shapes. If you have more, you can use letters instead.

Save your template. Then save the template in your Word Startup Folder for each user.

When your user presses Alt+S and then 1, the user will insert your first shape.

You originally asked about putting them on a Ribbon. This can be done but would require storing them as AutoText and then creating a ribbon tab, writing macros and assigning buttons. I don't know that this is worth it unless you really want to spend some time learning about ribbon customization and macros. See Customize the Ribbon (It doesn't take rocket science)