When most people train for a marathon, sex toys, pornography and Brazilian waxes are not part of the preparation.

However, Doug and Annie Brown’s marathon was a little different. The Boulder, Colo., couple – who had already been married for 11 years – were about to embark upon a marathon of 101 consecutive days of sex.

In the hilarious, romantic book, “Just Do It – How One Couple Turned Off The TV and Turned On Their Sex Lives For 101 Days (No Excuses!),” Doug Brown highlights how he and his wife set out to accomplish what seemed at times an impossible goal.

Recently optioned by 20th Century FOX, there is the possibility the book could make it to the big screen.

The story starts in September 2005. At the time, Doug and Annie were living in Denver, Colo., and Doug, a features writer for the Denver Post, told his wife about an unofficial club of people who had gone 100 days without sex.

That’s when Annie suggested they try the opposite.

“At first, I sort of thought, ‘That’s funny, ha ha,’” said Doug, 43, in a phone interview. “But, I know Annie pretty well and she loves a challenge. We talked about it more that night and the next morning, and I knew she was serious.”

It wasn’t like Doug and Annie weren’t having any sex at all.

On the average, they were having sex about once a week, “usually on Saturday nights,” said Doug, who still works at the Post.

Considering they both had jobs, and were raising their daughters Joni and Ginger, who are now 9 and 5, those numbers weren’t too bad, said FOXSexpert Dr. Yvonne K. Fulbright.

A 1994 study indicates that 30- to 39-year-olds are having sex an average of 86 times per year, and 40- to 49-year-olds are having sex an average of 69 times per year, Fulbright said.

“When Saturday night sex becomes routine, that is when couples need to make sure they are still wooing each other by incorporating spontaneity and novelty,” Fulbright added.

When I was around Annie in the evening, especially if I thought sex loomed (and during the marathon, it would loom over everything), arousal arrived like an intern on his first day at the firm: eager, earnest, attentive and bouncy with vigor ... Annie, on the other hand didn’t have an intern. She depended on a motley crew of part-timers who had to be called, with schedules that demanded massaging. To put it directly, I found it easier to crave sex on most nights than did Annie. Getting me in the mood, often took no more than a glance at her cleavage. Coaxing a thirst for sex out of Annie required more toil. Once the appetite arrived, though, it clamored for quenching.

Let’s Talk About Sex, Baby

“The next morning, I woke up and thought, ‘We really need to do this,” said Annie, 41, who works as a media analyst for Dow Jones. “Our marriage really needs to do this. That’s how it started.”

The marathon began January 1, 2006. They would need ways to keep it interesting, sexy. They started planning.

Annie’s ideas: Doug needed to replace his old sweatpants, the one with five pockets that he always wore to bed, with something more appealing. She would wear more lingerie and lipstick, and try a Brazilian wax.

Doug’s ideas: Annie should wear ‘sexy, thigh-high’ stockings. He would start working out. Together, they would visit the Adult Entertainment Expo in Las Vegas, which Doug was covering for the Post.

The sex project, I understood (ingeniously, I might add), offered the perfect rationale for convincing Annie that viewing porno together would be worth a shot. In the context of our sex experiment, we’d do it in the name of chemistry: Just add porno, and see what happens.

“You’ve got your porno. But, now it’s my turn. Sex toys.”

“Dildos?” I said, my heart pounding.

“I’ve got to research it. But I’m always hearing about how women are using sex toys. There are sex-toys parties. It’s on Oprah. It’s supposed to be healthy. I’m nearly forty, and I’ve never even touched one.”

I nodded slowly, but my mind was racing. What sort of Pandora’s Box have we opened?

The doctor’s ideas: Keep the bedroom door locked. Lubrication – and lots of it. Doug should eat fruits, since semen is “basic,” and the vagina is “acidic.” Annie, of course, would go on a birth control pill. Male ‘vitality’ herbs couldn’t hurt. Oh, and free samples of Viagra!

The rules: Oral sex was OK for foreplay, but in order for the encounter to count, it had to be intercourse. It had to be every single day, in sickness and health (including a bout of vertigo for Doug), through good times and bad (two big fights) and for richer or poorer (the marathon would require shelling out some extra money).

The bonus: After a spectacular finish on the 100th night, “we did it again,” Doug wrote in "Just Do It."

Doug’s co-worker at the Post approached him during the marathon (yes, they included their friends and family in on their sexcapade!) and suggested the Browns might do the deed one extra night – for good luck.

Getting It On . . . And On

Annie and I stayed up late poking around on the Internet. At 11 p.m., we still hadn’t even touched each other. When we finally did, Annie looked exhausted, and while my brain was zinging from the pill, my body was shutting down.

“What do you want to do?” asked Annie, stifling a yawn.

“I don’t know,” I answered. “What do YOU want to do?”

Said Annie: “Are we in seventh grade?”

“The hardest part, no question, was the tiredness,” Doug said. “You work, you commute, you have kids, you have to clean up, make sure they brush their teeth – by the time that part of the day is over, you are just tired and ready to zone out. That was the biggest impediment, getting past the fatigue. My body wasn’t used to ‘it’s Wednesday night at 9:30 p.m. and I’m going to have sex.’”

On top of the fatigue, Doug and Annie had to treat sex with respect. They couldn’t always just flop into bed and do the deed. They usually showered beforehand to wake themselves up, and lit candles in the bedroom, which they had dubbed the ‘sex den.’

“We weren’t doing it for the sake of doing it,” Doug said. “The point was to see what would happen. We treated it like we were dating again. We started looking forward to it.”

‘Just Do It’

The marathon’s benefits were overwhelming. Although their marriage was never really suffering, the marathon had renewed a spark and reminded them of the key ingredient that some couples tend to forget about – communication.

“I really think we communicate so much clearer and with so much more honesty (now),” Annie said. “There were so many times before that we hadn’t even hugged for like three days in a row. We gravitate toward rubbing each others’ backs more. We realize how important it is to put the kids to bed and spend time together.”

We’d done it in a basement, a Las Vegas casino, a classy hotel, a Victorian bed-and-breakfast, and a yurt. We’d had early-morning sex, late-afternoon sex, and lots of evening sex. Nor will we forget the sex we had on the side of a cliff during our “training” period just prior to the kickoff of the marathon ... We’d traveled far. We knew we’d come back to our lives removed from the adventure’s rigors soon, but it seemed likely that things would be different, had to be different. We’d seen and felt and tasted so much. Adequacy no longer was acceptable: We demanded panting flesh, ravishment. We’d grown spoiled.

Even if Annie and Doug’s love story never makes it to the big screen, they are happy with the book’s success and hope its message reaches other couples.

“I would love to see this conversation in every home in America,” Annie said. “Gay, straight, with kids or without – this is a conversation that people shrink from and yet it’s so important. Once you stop making love to your partner, you become roommates. Whether it’s five times a month, or three times a month, just being comfortable with that number is most important.”

And for those of you wanting to try your own ‘marathons,’ Doug and Annie suggested starting out on a smaller scale – say, five or 10 consecutive days.

“Make sex a priority,” Annie said. “Stop watching TV and bringing the laptop to bed. Stop multi-tasking. Just listen to one another. And hire that housekeeper – even if it’s only once a year or once a month.”