$banners = array('txt1','txt2','txt2','txt4','txt6=5',);
$cc = count($banners) ;
$cl = $cc-1;
do {
$rand = rand(0,$cl);
$rand2 = rand(0,$cl);
$rand3 = rand(0,$cl);
}
while ($rand == $rand2 or $rand2 == $rand3 or $rand == $rand3);
echo "
$banners[$rand]<br/>
$banners[$rand2]<br/>
$banners[$rand3]<br/>
";