Mailbox-to-mbox

Hello,
lately I've been looking for a way to convert a mailman archive to an mbox format so that I could open with mutt.
I then found a couple of scripts, but the one I've found simpler and working for my needs is mailbox2mbox.pl.
Sample usage:

$ gunzip YourArchive.txt.gz
$ perl mailbox2mbox.pl < YourArchive.txt > mbox
$ mutt -f mbox

And it simply works!
Does anybody know a method as simple as the above one but more powerful?

PS: Happy holidays!