Based on what was just said, my example can be simplified even further:

# this is what should be used instead of the hard-coded value:
# my $today = strftime("%m-%d-%Y",localtime());
my $today = '08-14-2013';

my @todays;
for ( @orig_data ) {
    next unless m/^($today )/;

    push(@todays,$_);
}

# NOTE! this will reverse the order of Yes and No if they have the
# same time.
@todays = sort(@todays);

for ( @todays ) {
    print "$_\n";
}
[download]

I agree that filtering then sorting will result in (sometimes large) performance gains. In this particular case, where the unsorted array is actually records coming from a file, you only want to store the records of interest in memory instead of slurping in the entire file. RAM might be cheap, but it is a finite resource and SAs can be a nasty breed of cat. (Remember the BOFH?)