Copy and paste the code into a blank php file and enjoy 
{
$cal_weeks_days .= ‘
$ii = 1;
}
// If the day is the current day, highlight it with a special color
$extra = ($current_day == $day_i) ? 'background-color: ' . $row_highlight_color . ';': 'background-color: ' . $color . ';';
// Show the days.
$cal_weeks_days .= '<td valign="top" style="' . $extra . ' height: 65px;">' . $day_i . '</td>';
// Increment the day number and the week day number (ii)
$day_i++;
$ii++;
}
// Add end month spacers
if ((8 - $ii) >= 1)
{
$cal_weeks_days .= ’
}
// Echo the VALID HTML
echo <<< HTML
<html>
<head>
<title>Valid HTML Simple Calendar by Acecoolco</title>
<style type="text/css">
table,tr,td,th,tbody,TR,TD{
font-family: Verdana;
font-size: 8pt;
font-size: 11; color: #000000;
border-font-size: 11; color: #000000;
border-collapse: collapse;
}
</style>
</head>
<body>
<table border="1" cellpadding="1" cellspacing="1" width="$calendar_width">
<tr>
<td align="center" colspan="7" bgcolor="$row_head_color">$current_day_name the $current_day_S of $current_month_name, $current_year</td>
</tr>
<tr>
$day_names
</tr>
<tr>
$cal_weeks_days
</tr>
</table>
</body>