The always worth a look Msgr. Charles Pope, on worthy reception of the Blessed Sacrament.
He's got a hard sell, there, as his argument rests on the concept of sin -- which, we know as modern, rational people is a mythical substance, right?
(Seriously, though, you must catch the comment wherin a parent recounts attempting to get our need to TRY to be worthy-though-unworthy-we-be across to her child, and teaching Truth in a way I think very few parents are making the effort to do. Brava.)