This is easy (Score 1)

So you suspect that your paswords are crackable? Here's an obvious idea: Every week run a 4 hour crack attempt on your password database. Users who come up with bad passwords must change them upon the next log in. If a user can't pick a decent password 3 times in a row, then a random password is assigned to them (or you pick one for them).

Shzaam@! No more bad passwords!