If you're adept, you can use them to install subroutines on the fly, the first time they're called (instead of compiling everything at the beginning). Not only does that save you a bit of typing if you have many similar methods (accessors -- get_variable, set_variable), but if your program only uses a few at a time, you get a bit of a speed benefit.

If you were really tricky-minded, you could add new subroutines on the fly, with some eval magic. Rough, untested code follows, as I'm not completely positive of the AUTOLOAD syntax without checking a book:

sub AUTOLOAD {
    next if $AUTOLOAD =~ /DESTROY/;    # be safe
    my $sub_text = shift;
    $AUTOLOAD =~ s/.*:://;
    eval qq|*{$AUTOLOAD} = sub { $sub_text };|
    # the following goto may require
    # no strict 'refs';
    goto &$AUTOLOAD;
}
[download]

That's deep magic, and you'd better understand exactly what it does before you even think about using it. (There are only a couple of situations where I'd consider using it, and it would most definitely NOT be available to anyone off the street. Big security risk here.)

Update: I added the goto line because jlistf made me think of it.