Don't laugh--it's my first golf. 55 chars, appears to follow the rules.

$,=$";print sort{$b<=>$a}(ord(b)-ord a)..(ord(k)-ord a)

UPDATE: This occurred to me about five minutes after that one. 45 chars.

$,=$";print sort{$b<=>$a}map{ord()-ord a}b..k

=cut
--Brent Dax
There is no sig.