Sure, your younger kids will be content to overturn buckets of sand to make simple castles, but if you're taking older kids to the beach this summer they may be up for more of a challenge. The Sandcastle in a Box kit is both book and tools to teach you and your kids some of the finer details of building more intricate sand dwellings. Best of all, it's not much bigger than that trashy novel you're bringing to the beach yourself so it won't take up much room in the car or your suitcase.
Sandcastle in a Box comes with an illustrated 64-page book written by master sand "sculptor" Ted Siebert. You also get a skewer stick, small shovel, window template, cylinder mold, palette knife with rounded tip, funnel, turret flags, a brush, and a tool bag to hold it all. It sounds like this could occupy your kids for hours or be a fun activity for the whole family.
You can find it here ($12).