displays a random item from an unordered list (like for random promo images)

showRandomItem

//todo: de-jquery this
function showRandomItem(list) {
    // random ad on refresh. Each a element should have style="display:none"
    var items = $(list).children('li'),
    	tot = items.length;
    if (tot > 1) {
        var randNum = Math.round(Math.random()*(tot-1));
        items.eq(randNum).show();
    } else {
        $(items).show();
    }
}