How I got addicted to playing games on my iPhone.

Last month, I became an obsessive air-traffic controller. The culprit: a terrific game for the iPhone called Flight Control. The premise is simple: You're faced with a crush of planes, and it's your job to guide each one to its respective runway. The gameplay, though, is irresistibly difficult. A few minutes in, the planes start to show up at an alarming rate, and you scramble to keep them from crashing into one another. When they do crash, the game beckons you to play again. Flight Control is so addictive it ought to come with a warning label. According to Firemint, the game's publisher, the 99-cent app has been purchased more than 700,000 times since March; at its peak, it was being downloaded 20,000 times a day.

As I succumbed to Flight Control, I tried to puzzle out what made it so hard to put down. Sure, it's well-designed and fun. But there's something else about the game that's infectious: You can play it anywhere, in those moments in the day when you're otherwise unoccupied, bored, and alone. Because the game is repetitive, a bit mindless, and brief—you can play it for a couple of minutes, then put it away—it expands to occupy all your time. I've loaded up Flight Control while standing in line at the supermarket, while waiting at the doctor's office, and during bouts of insomnia. Also, of course, in the bathroom.

When I tell people that my iPhone isn't a very good phone—its reception in my apartment is so terrible that I reach for Skype as an alternative—they look at me as if I'm an idiot. Why pay all that money for a phone that doesn't phone? But the iPhone's name is a marketing trick; it's really a mobile computer that I occasionally use to make crappy phone calls. As Flight Control shows, it's also a game system. While it lacks the features of proper mobile game devices like Nintendo's DS, the iPhone (and its phoneless sibling the iPod Touch) has a few key advantages over those dedicated devices—you carry it everywhere, and it's always connected to a vast storehouse of cheap, addictive games.

I've never been much of a gamer, so I've never had a DS or any other handheld. How did Apple turn me into a gaming obsessive? Since the iPhone's games go for a buck or two a piece, they're not much of a risk, and many follow the recipe for great games once put forward by Nolan Bushnell, the founder of Atari and Chuck E. Cheese: They're easy to learn but difficult to master. Nongamers will get the hang of Flight Control in a few seconds, but you'll tear your hair out trying to land more than 50 planes—and you'll keep trying. In the meantime, while you weren't looking, the iPhone turned you into a gamer.

It's true that there are many sprawling games in the App Store—titles like Oregon Trail, which takes days to finish, or SimCity, which never really ends—but some of the platform's most successful developers are the startups and one-man shops that can't afford to produce huge games. Instead they make small, easily digestible titles that appeal to a wide audience. The first developer to crack this code was Ethan Nicholas, whose tale of quick riches achieved the level of myth earlier this year. Nicholas was a programmer at Sun Microsystems who'd been facing some unexpected financial difficulties, and he took up iPhone programming as a way out of his problems. Last fall, he spent weeks—some of it while cradling his 1-year-old son—writing a tank-war game called iShoot. The game, which sold for $2.99, hit the App Store in October, and in January, it shot up to the top spot—selling hundreds of thousands of copies and earning Nicholas enough to let him quit his job and take up iPhone development full-time.