Use with an argument of "yyyy-mm", or with no argument to get the current month. I made this because it was easier than hacking the existing cal tool to do what I want. This snippet is very configurable, but only by hacking its source :) 
#!/usr/bin/perl -w

use strict;
use Calendar::Simple qw(calendar);
use POSIX qw(strftime);

my $today = strftime '%Y-%m-%d', localtime;
my ($year, $month) = split /-/, shift || $today;

printf "\n%04d-%02d\n\n", $year, $month;
print "\e[1mMon Tue Wed Thu Fri Sat Sun\e[0m\n";

for (calendar $month, $year, 1) {
    for (@$_) {
        no warnings;
        $_ = sprintf '%3s', $_ || '';
        $_ = "\e[7m$_\e[0m"
            if sprintf("%04d-%02d-%02d", $year, $month, $_) eq $today;
    }
    print "@$_\n";
}
print "\n";

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In reply to Very simple calendar by Juerd

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