How can I setup a reminder email tool via procmail?

"Something like this in .procmailrc:

* ^From: me@example.com
* ^To: mycalendarservice@example.com
| somescript.pl

somescript.pl will get the mail on standard input, so you could parse it apart like this:

while (<>) {
/^Subject: (.*)/ and $cmd = $1;
/^./ and $body .= $_;
}
chmod $cmd;
open(OUT, ""| $cmd"") or die;
print OUT $body;
close OUT;

Be sure to make this safe from abuse."