With a little modification, a 1.0 approximator:

OneFoo

#!/usr/bin/perl

# Two Monte Carlo approximations of 1. Slow!

use strict;
use warnings;

my $in    =  0;
my $count = @ARGV ? shift : 1000;

rand () + rand () < 1 && $in ++ for 1 .. $count;
printf "One equals %f\n", 2 * $in / $count;

$in = 0;
rand () < .5 && rand () < .5 && $in ++ for 1 .. $count;
printf "Or maybe %f\n", 4 * $in / $count;
[download]