Vertex Groups in Blenders 2.69 Cycles Render

I can’t seem to get the vertex groups working correctly in Blender 2.69 cycles render. When I assign vertex groups using a simple cube the whole cube changes to the new material color I try to assign to it. What am I doing wrong here?

Vertex groups usually don’t have anything to do with materials. What are you trying to do exactly?

You assign materials colors in the material panel while in Edit Mode, not with vertex groups.