my $rows;
my $class = 'odd';
for my $name ( qw(Odd1 Even1 Odd2 Even2) ) {	
	my $hash = {
		name => $name,
		class => 'row_color_'.$class,
	};
	push(@$rows,$hash);
	$class = ( $class eq 'even' ? 'odd' : 'even');
}
$template->param(DATA => $rows);

##</code><code>##

<TMPL_LOOP NAME=DATA>
<tr>
<td class="<TMPL_VAR NAME="class">"> Row <TMPL_VAR NAME="name"></td>
</tr>
</TMPL_LOOP>

##</code><code>##

<tr>
<td class="row_color_odd"> Row Odd1</td>
</tr>
<tr>
<td class="row_color_even"> Row Even1</td>
</tr>
<tr>
<td class="row_color_odd"> Row Odd2</td>
</tr>
<tr>
<td class="row_color_even"> Row Even2</td>
</tr>