Have you wanted to hide the ribbon on your SharePoint 2010 site from Anonymous users, or at least part of the ribbon? There is a great article here on doing this, but for my case I had to make some slight modifications. In particular, I didn’t want to hide the entire ribbon, rather I wanted to hide the site actions menu only.
First, as a quick review, there is a great tag the SharePoint allows:

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<<span class="purple">SharePoint:SPSecurityTrimmedControl</span> ID="SPSecurityTrimmedControl2" runat="server" PermissionsString="ManageSubwebs" />

You can place this tag around most any block of code, and by replacing the PermissionsString value, you can dictate what permissions are required to display the block of code. Most suggestions have been to place this tag around the entire ribbon, but that was overkill for what we wanted.
Also you can edit the <SharePoint:SPRibbon> tag decloration to require certain permissions to display certain features, but that will not necessarily remove the site actions. Add a PermissionsString value to the <SharePoint:SPRibbon> tag to hide parts of the ribbon, but not all of it.
Ok, so what we did.
First we modified the

tag as follows:

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<<span class="purple">SharePoint:SPRibbon</span> runat="server" PlaceholderElementId="RibbonContainer" PermissionsString="EditListItems" CssFile="">

This will allow most of the ribbon to be hidden from anonymous users, but the site action menu will remain. So then hide the site action meny from anonymous users, we added the following

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<<span class="purple">SharePoint:SPSecurityTrimmedControl</span> ID="SPSecurityTrimmedControl2" runat="server" PermissionsString="ManageSubwebs">

around the site action tag, which looks like:

<!-- site actions -->
<span class="ms-siteactionsmenu" id="siteactiontd">
    <SharePoint:SiteActions runat="server" accesskey="<%$Resources:wss,tb_SiteActions_AK%>" id="SiteActionsMenuMain" PrefixHtml="" SuffixHtml="" MenuNotVisibleHtml="&nbsp;" >

 
Don’t forget to add the closing

tag after the close of the site action’s

.