<var columnClass="new [] {'span-11 column', 'span-11 column last' }" />
<div each="var item in o.Items" columnClass="${lastClass[itemIndex%2]}">
 
</div>

Original HTML+BluePrintCSS
 
<div id="header" class="container">
    <div id="title" class="span-10">
        <h1>${H(ApplicationName)}</h1>
    </div>
    <div id="logindisplay" class="prepend-8 span-6 last">
        <logOnUserControl />
    </div>
    <div id="menucontainer" class="span-24 last">

#header {
    #title {
        .span-10, .column;
    }
    
    #logindisplay {
        .prepend-8, .span-6, .column, .last;
        text-align: right;
    }