Believe it or not, we use the same PPP format common in agile dev shops. However, instead of "Progress, Plans, and Problems," we use "Victories, Goals, and Help Needed" to give it a slightly more optimistic and personal feel. We also set aside time to discuss big picture items (such as challenges at work, medium and long-term relationship management, housing repairs, etc.).

We don't have kids, but if we did, we would definitely use this time to sync up about that. Make sure we both know what activities they have coming up and/or shared understanding of how to love, praise and discipline them.