This hasn't been tested but maybe it can give you something to start with.

#!/usr/bin/perl
use CGI qw:/standard/;

@year = qw(January Feb Mar Apil May June July Aug Sept Oct Nov Dec);
$month = param('month');
$day = param('day');

print header;
print " <form><select name=month size=12>";
    for (@year) { print "<option value=$_>$_</option>\n"; }
print "</select>";
print "<select name=day>";
    for (1..31) { print "<option value=$_>$_\n"; }
print "</select><input type=submit ></form>";
if (param('month')) {
if (($month eq 'January') && ($day > 20) || ($month eq 'Feb') && ($day
+ < 20)) { print " You are an Aquarius"; }
# and so forth for the rest of the months...
}
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