What would you do if you could stay awake and alert for 40-hour stretches?

Label your videos and organize your closets while the world slept? Drive straight through from the District to Santa Fe, N.M.? (That's 31 hours' road time, plus eight hours for bathroom and food breaks.) Start your novel? Party till you didn't drop from exhaustion?

Prepare to find out. You've probably heard a lot less about the drug modafinil than you have about Viagra, but I'm convinced that will change. Why?

Because Viagra addresses male sexual dysfunction, which only affects millions of men and their partners. Modafinil shuts off human beings' urge to sleep.

Who doesn't that affect?

As someone who's been sleepy for two decades -- my eldest child is 20 -- I read Post reporter Joel Garreau's article about the drug with excitement and dismay. In trials on healthy people, modafinil allowed users to stay up for almost two days while remaining nearly as focused, alert and capable of problem-solving as the well-rested.

After eight hours of sleep, Garreau writes, users can rise and go another 40 hours. Reportedly, modafinil users don't experience the jitters or addiction -- with its euphoric ups and spiraling downs -- suffered by users of amphetamines, cocaine and even coffee.

Considering its downside, why is caffeine the world's most widely used drug? Why is there a Starbucks on every other corner?

Because most Americans don't get enough sleep -- two-thirds of us, according to the National Sleep Foundation.

So why aren't people more excited about modafinil? The military may salivate at the prospect of an ever-ready "24-hour soldier"; my friends with young children sigh at the notion of being awake enough for occasional lovemaking.

But when I described the drug to my manicurist, she responded, "No way. Why would anyone want to stay up 40 hours?"

"Forty hours? That's scary," echoed bakery manager Melbin Perdigon, 25. "Maybe if you were doing a really long drive . . . "

Silver Spring artist Ellen Jacobson was leaving a video store, clutching "The Princess Bride." Exhausted by her son's graduation, Jacobson hoped her daughter, 5, would watch "Princess" while she napped.

But pop a pill to eradicate her sleepiness? Please.

"We have life cycles for a reason," said Jacobson, a potter and painter. "If people have that much to do, they should cut some things out and prioritize."

So she'd never consider modafinil?

Pause. "Maybe when I'm getting ready for my holiday sale. . . . But it would seem like you'd be going against nature.

"This is not going to solve the problem of time."

Time, we long ago decided, is the Enemy. Despite our desperate battles with it, our endless manipulations, it ticks on -- taking a toll on our bodies, minds, careers and every relationship we find too little time to nurture.

So we worry, plan and strategize. We introduce our skin to industrial-strength moisturizers, our bodies to energy boosters and memory enhancers, our kids to after-after-school care and marathon TV sessions. We spend more time working than we would like.

Forty more hours a week? We'd probably do more of what we regret doing now.

Even sleep researchers who tout modafinil wonder about its long-term effects. Accumulated sleep deprivation is suspected of causing obesity and illness. Still, modafinil, currently marketed to people with sleep disorders, is bound to be sought by truck drivers, hospital interns, pilots, exam takers -- and everybody else who pulls all-nighters.

In a world of 24-hour laundromats, diners, shopping services, TV channels and copier stores, that means millions.

Who won't go for it? Those who, realizing that the body repairs itself during sleep, believe that not sleeping for extended periods must be physically harmful. But what of the soul? Is tampering with something as fundamental as sleep . . . wrong?

Even God rested after His labors.

District pastor Allen White, who says he hates sleep because he would rather stay awake to play the piano and pray, says modafinil reminds him of Psalm 127: "It is vain for you to rise up early, to retire late, to eat the bread of painful labors; for He gives to His beloved even in his sleep."

Even without our constant labor, the passage suggests, God provides.

"It means we can go to sleep and everything will be all right," says White. "People think if they're not doing something every second, nothing will get done. That's vanity."

That's life as many of us know it. If modafinil scares you, don't even consider the next generation of "wake-performing" drugs. Scientists say they'll keep us awake indefinitely -- without adding sleep debt.

Decades from now, people wary of modafinil may seem as quaint as those who once said, "If God wanted man to fly, He'd have given him wings."

But we'll be too miserable from never getting a break from our ever-wakeful families and co-workers to take any pleasure in it.