sub by_time
{
    # $a and $b are things to be compared from sort()

    # Convert $a and $b into integer values

    # Extract the time from the string into $a_v
    my ($a_v) = $a =~ / (\d\d?:\d\d:\d\d)/;

    # Remove colons to create a numeric-only value
    $a_v =~ tr/://d;

    # Same for $b
    my ($b_v) = $b =~ / (\d\d?:\d\d:\d\d)/;
    $b_v =~ tr/://d;

    # Return the difference (0 = same)
    return $a - $b;
}

foreach (sort by_time @stuff)
{
    print "$_\n";
}