would be simple to add to the forum.tpl

basically, you add something like

{if $smarty.section.fora.iteration is odd} alt-forum-bg{/if}

to the <td class="xxxx".... > elements inside the fora, section

example:
Code
<td class="forumtitle{if $smarty.section.fora.iteration is odd} alt-forum-bg{/if}" valign="top" align="left">

do that for each column td and bada bing..

then add the .alt-forumlist-bg class to style the alternate BG background-color:#xxx; in the Extra CSS section smile