Oh, man, David... he was just begging for someone to bite. You couldn't resist, could you? ;D
;D
Drupal, blah, blah, blah... .NetNuke, XOOPS, Achoo! I think I've played with them all.
I have a buddy who swears by Expression Engine. Not open source, but he says that's part of the beauty.
JOOMLA!
I'm too stupid or too old to learn something else.