Well I'll have a go:

#!/bin/perl -w
use strict;

# slurp it up
$/='';
my $slurp = <DATA>;
# one nice string might as well split it
# adding a little whitespace gobble and case protection
my @stuff = split(/\s*<\s*[Hh][Rr]\s*>\s*/,$slurp);

# and spit it out
foreach (@stuff) {
  print $_,"\n";
}



__DATA__
<HR>
1 is good<BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
2 is not good <BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
3 is good<BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
4 is not good <BR>
useless data<BR>
useless data<BR>
useless data<BR>
useless data<BR>
<HR>
[download]

mitd-Made in the Dark
'Interactive! Paper tape is interactive!
If you don't believe me I can show you my paper cut scars!'