I'm about to make the smartest purchase of my life, or the dumbest.

Before I tell you what it is, let me tell you why I'm doing it, because that's even dumber, or smarter, depending on how the story ends.

I first saw one of these contraptions last year, when I happened to be doing research online.

OK, I admit, I was wasting time online.

Which might be redundant.

Yesterday, I happened to be wasting time online again and I kept noticing sidebar ads popping up, which as we all know now are based on the things tracking our online behavior. They call the things that do this cookies, but if you ask me, it's the one kind of cookie I don't like.

In other words, chocolate chips taste better than computer chips.

Anyway, the cookies in your computer send you ads about the products you've looked at in the past, and if you're middle-aged like me, you forget you've been looking at these products, so when the ads pop up and offer you these products, you get the eerie sensation your computer is reading your mind.

When it's just that your computer has a better memory than you do.

To come to my point, a long time ago I was kind of curious about treadmill desks, because it seemed like such a crazy thing to me. If you don't know what a treadmill desk is, it's a special treadmill that only goes 2 to 4 miles an hour, or walking at a slow pace, and it's outfitted with a desktop that is eyeball-height, so you can work on your computer at the same time you're standing up and walking on the treadmill.

Ridiculous, right?

I thought it was, too.

So ridiculous, in fact, that I was actually going to write about how ridiculous it was that people have to be working so hard and multitasking like crazy, so that they can't even take time from work to take a walk, for God's sake.

And of course the very notion of working while on a treadmill is too good a metaphor for a writer to pass up.

The only thing better would be a rat in a race.

The rat race, get it?

Does anybody still even know that expression?

OK, so to get back to the story, there I was online and all of these ads kept popping up for treadmill desks, and since then I've started having back problems from sitting so much for work. In fact, the physical therapist told me my back would benefit if I switched to a standing desk.

I need a desk for my discs!

But I'm never one to leave well enough alone.

Why get a standing desk when you can have a walking desk?

I mean, why should your desk just get to sit there, doing nothing?

So I clicked on the ad for the treadmill desk.

And I started reading.

All of a sudden, it started not to seem so ridiculous anymore.

In fact, the company that makes the desks says it makes fitness-at-work products that "target the 55+ health-conscious consumer."

I instantly thought, ME!

So I spent some time on the website, watching the sales video of the people happily typing away on their computers while they were walking on treadmills.

And I wanted to be one of them.

The only hard part is that I'm not sure I have that degree of coordination.

You have to be able to pat your head, chew gum, and write a novel, all at the same time.

Normally I can only do one of these at once.

Chew gum.

I researched the customer reviews of the treadmill desks, and the idea started to grow on me.

So I'm buying one.

The moral of the story is that sometimes things that look ridiculous might turn into a necessity, which is a moral I forgot when I saw elsewhere on the website that they actually sold desks attached to bicycles.

A cycling desk?

Now that's ridiculous.

I think.

Look for Lisa Scottoline's new novel, "Betrayed," in stores now. And look for Lisa Scottoline and Francesca Serritella's latest humor collection, "Have a Nice Guilt Trip."