Some or all of the modules already listed do this. Core module Time::Local also does. 
use Time::Local qw( timelocal );

my $date = '10/15/2008';

my ($m, $d, $y) = split(m{/}, $date);
my $time = timelocal(0, 0, 0, $d, $m-1, $y);
my $dow = (localtime($time))[6];

if ($dow == 5) {
   print("It's Friiiiiiiiday!\n");
} elsif ($dow == 0 || $dow == 6) {
   print("Sweet heavenly weekend!\n");
} else {
   print("Get back to work, you bum!\n");
}

[download]

In reply to Re^3: is today a friday by ikegami
in thread is today a friday by baysbenj

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.