Editor's Note:

A few years ago, I became obsessed with an extremely primitive video tennis game. I played it endlessly, until I sobered up and kicked the habit. But since I was planning to write about video game obsession to introduce today's story on a man's slavish devotion to the retro arcade game Donkey Kong (Page 16), I figured it would be legitimate research for me to play the game once more, just to remind myself why it was so addictive.

Well, I can report after playing it, um, repeatedly, that I have absolutely no idea what it is that pulled me in so strongly. But I can tell you this: I . . . can't . . . stop.

It's called Tennis Ace, at a free game site (miniclip.com), and it features crude graphics of cartoon tennis players in a stadium. You can choose to play on clay or grass, but the only difference is the color of the court, red or green. The sound effects are rudimentary, too: a robotic announcer, canned applause, a very satisfying thud every time a cartoon racquet meets the cartoon ball. You control your player with the mouse and left-click when you want to swing. Like many video games, this one has levels of difficulty. On level 1, you'd have to be in a coma to lose. Level 2 is good practice. After a few games, you can learn to beat the computer consistently. Level 3, the highest level, is challenging. At first it seemed unbeatable, but as I played and played, I began to come close -- close enough to keep me trying, game after game after game. And then, finally, one magical night, I beat it.

Victory gave me an absurd feeling of power and accomplishment, even though I had done nothing more taxing then click my index finger. For three hours.

And maybe that's the answer. The computer fools your brain into believing that you've done something -- or may be about to do something -- heroic, while in reality, you've done almost nothing at all. My guess is that a hugely unbalanced reward/effort ratio is addiction's prime mover.

I went cold turkey after that -- hadn't played once until today, as I was writing this column. But I did think about it. It fed my resistance to installing an elaborate game system in our basement -- and possibly entrapping my kids in the gaming web that seems to have snared their generation. I remember the kind of childhood in which packs of kids raced around outside from one adventure to the next, until dark or cold or rain chased us home. I can still feel how that shaped me, forging an eagerness to be out in the world doing, exploring, taking on challenges. The only thing playing video games inspired in me was a desire to play more video games.

Tom Shroder can be reached at shrodert@washpost.com.