open(AT, "|at now + 2 minutes") or die "...";
print AT "/....../mifuture.cgi idnumber=220\n";
close(AT) or die "...";    # non-zero exit status

##</code><code>##

fork && exit;    # CGI script returns/exits right then

# This continues processing in the background
while ($_ = shift(@things_to_do)) {
   sleep $seconds;
   process($_);
}