Use the portable post-it flags to write down your different dinner entrées. Use different colors for each category (beef meals get a red flag, chicken yellow). You can plan your menus for the week by sticking the flag on the calendar day you plan to have the meal. If you need to switch just move it.
This works on a kitchen wall calendar or your personal calendar. It allows you to plan for eating out or "planned overs" for the week. If you generate enough menus for 2-3 weeks you'll keep the "what's for dinner?" complaints at bay. It also allows flexibility for the crazy last minute family stuff.