Our marriage has proven to be a sixteen-year failed experiment in... responsible credit card use. There is something about being able to have something now and pay for it some other time that my wife and I just can't get past. It's actually caused a lot of problems for us, and we've tried a number of solutions that have ultimately failed.
This year we are trying prison. Not for us, but for the cards. We rented a safe deposit box and every non-gas credit card goes into it and stays there except for trips. (The runner up solution: freezing the credit cards in a block of ice--a fun idea from Ben).
We have also switched over to a cash economy... pay the bills with the checkbook and put the checkbook away for the month. Each week we withdraw whatever food & everything else money we have allotted, and that's it. If we want to know if we can afford something, we look in our pockets: if we have money, we can.
At some point aren't I supposed to become mature and be able to handle these kinds of things?