Here is a screen shot of the data on the page - I have information grouped, and when you expand the group you can see the alternating row color. Here is where the inbetweener comes in. I didn't like the out-of-the box color that was applied to the row color, so I changed it using SharePoint Designer.
It's not wise to modify the out-of-the box styles from sharepoint but you can override them by using the following CSS code:
.ms-alternatingstrong {
background-color: #F2F1EC !important;
}
You should obviously #F2F1EC with your preferred color - although my warm grey is quite nice.