I guess it's the fundamental, innate human need for shelter, or possibly the basic desire to make the biggest possible mess just in time for Dad to get home.

At any rate, may I present: Fort Wamsutta! All 72 rooms of it. It spans chairs, tables, plants, stuffed animals, and the occasional sport utility vehicle. But never (again) the ceiling fan.

I'm not sure where kids come up with this idea, but I'm pretty sure that in each and every case, it's completely original. A developmental step, like recognizing the alphabet, or realizing that food sticks to the wall. One day the light bulb just goes ON, and forever after you get to stockpile old sheets, rather than hauling them to Goodwill (for fear of possibly losing some drapes to the cause.)

I've forbidden the use of my best white sheets, and my little architects respect that most of the time. The difficulty there stemming from an unfortunate incident involving a peanut butter and jelly riot in Colonel Max's mess hall (involving a large percentage of the cavalry.) Jelly stains, you know.

Half of the adventure is the trip upstairs (ALONE) to the spooky linen closet to fetch the coveted building materials. This is not technically engineered as a preventative measure, but it slows them down a bit. Enough for me to wrap up what I'm doing, pour myself a good stiff lemonade, and make a bowl of popcorn. Watching my kids make a fort out of sheets and blankets is pretty much worth the $5 admission.

They really have no concept of counterbalance, or any other basic premise of physical science. But on the other hand, their requirements on ceiling height are pretty forgiving, and their standards on structural integrity quite low. At any rate, I can pretty much imagine what the first two little pigs were thinking.

My kids, for example, don't seem to understand that you can't successfully weigh down a "queen size flat" with a golden book. Maybe a twin superman 180-count, or a snoopy pillowcase, but definitely not a queen size. They also haven't figured out the obvious need for architectural supplements like the invaluable "broom prop," the upright vacuum cleaner, and the clothesline ridge. They'd have probably passed up the coat rack, had I not brought it to their attention, with an absent wave of my pretzel stick. What, do you think we keep that for coats? We live in Florida, for Pete's sake.

Forget the coffee table; think BIG! A good blanket fort ought to bear remarkable resemblance to your average moon colony by the time it's finished (usually dinnertime.) This is not a firm requirement, just a rule of thumb. It also ought to leave a window open facing the TV, so exhausted workers can settle in after the demands of construction-type activity.

Having fashioned the requisite shelter, blanket fort denizens should also address the second basic human necessity: food. Technically, the human need for food is FIRST, and supersedes the need for shelter, but my little heathens eat a big lunch. Plus, they mooch a lot of popcorn.

Fort food is never nutritious. The guys who built the pyramids or the Taj Mahal didn't plop down afterward and declare "I think it's time for a SALAD." Seriously, if there isn't a cheeto in there somewhere, it just wasn't worth the effort. Chocolate milk is the libation of choice for my exhausted crew. Lots of froth. And a straw, if possible.

As far as testament to a day well spent, there's not much that can beat a well-constructed blanket fort. The sense of pride and accomplishment hasn't changed much since I was a kid (not to imply that I'm a grownup now, or anything…) How long has this tradition been around? I wonder what kids did in the stone-age. Did they make caves out of their mothers' best rocks? Did they make nearly as many crumbs? And (here's the biggie) did they put them back when they were finished. All current indicators point south on that one.

So, enough reading, grab a corner. Fort Wamsutta's got to bug out before the Big Bad Wolf gets home.