my @days = qw( Monday Tuesday Wednesday Thursday Friday Saturday Sunday );
my @hours = (7..21); # use the start hour for the value;

my $out = qq(<tr>
               <td>Day</td>);
for my $hour (@hours) {
$out .= "<td>$hour - " . $hour + 1 . "</td>";

for my $day (@days) {
$out .= qq(  <tr>
   <td>$day</td>);
  for my $hour (@hours) {
   $out .= qq(<td><input type="checkbox" name="$day" value="$hour" /></td>);
  }
$out .= qq(</tr>);
}

# so now you've printed out the form;
# now to get the data out of it:

use CGI;
my $q = CGI->new;
for my $day (@days) {
@hours = $q->param($day);
# the hours for the day are now in the array.
$Hours->{$day} = \@hours;
}