In an age when the latest video games sport ultra-crisp graphics and cinema-like sound, there is still plenty of love for the good old-fashioned games just like Mom and Dad used to play.

Games such as "Pac-Man" and "Space Invaders" are enjoying a resurgence in popularity as technology gets cheaper and new online services make them easier than ever to download and play.

"I'll tell you, the retro games really have resonated. They are some of our top selling titles," said Greg Canessa, group manager of Xbox Live Arcade, Microsoft Corp.'s (MSFT) online service, which lets users of its Xbox 360 console download "casual" games.

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Fans are typically older players who grew up in the 1980s plugging pocketfuls of quarters into arcade games or who gave themselves blisters working joysticks on early home machines like the Atari 2600.

"Not to get too deep about it, but 9/11 seemed to create a great level of nostalgia and cocooning, and had a deep effect on the American psyche," said Eric Levin, executive vice president of Techno Source, which makes a line of "plug and play" gaming devices.

But classic games — if that term applies to a medium that has only existed in mass market form for about 30 years — are also finding appeal among younger players.

IT'S ALL ABOUT GAMEPLAY

Early games bear about as much resemblance to today's top titles as a cave painting does to the Sistine Chapel. Compare the monochrome minimalism of "Asteroids" to the cinematic detail of "Halo 2."

Yet what was fun 25 years ago still holds appeal today. In the end, it's all about the gameplay.

"You can take some of these games, which take a minute to learn but a lifetime to master, and you can play them with your kids," Levin said. "We've not only appealed to the people who had them as kids, but we've attracted new players as well."

The technological law that boosts the power of microchips while lowering their cost means that a collection of games and hardware that would have cost close to $500 in 1980 can now be sold by Techno Source for about $10.

The company's gadgets plug into a TV and are preloaded with 10 games, including console classics such as "Pitfall" and "Kaboom!" from Activision Inc. (ATVI).

Many old games have also been dusted off to play on today's high-end game consoles from Microsoft, Sony Corp. (SNE) and Nintendo Co. Ltd.

One example is "Intellivision Lives" published by Crave Entertainment — for the Xbox, PlayStation 2 and GameCube — which packs 60 games from Mattel Inc.'s (MAT) 1980 console and sells for $20.

GOING MOBILE

The simplicity and low cost of retro games also makes them ideal to squeeze into portable devices like mobile telephones or even digital music players.

Last month, Apple Computer Inc. (AAPL) said new versions of its iconic iPods would sport video games such as "Pac-Man" and geometric puzzler "Tetris."

Microsoft is cashing in on gaming nostalgia, but Canessa said it's easy to forget that there were plenty of horrible games at the dawn of the industry.

"Most of those games, frankly, are fun for 5 or 10 minutes, but you kind of had a better impression of them back in the day than you do today," Canessa said. "We pick just the best games, the games that are as fun to play as they were 25 years ago."

Microsoft has rolled out a steady stream of classics, such as "Galaga," "Joust" and "Time Pilot," on Xbox Live Arcade, updating them with prettier graphics, online play and support for high-definition televisions.

More games are sure to be in the pipeline as the definition of "retro" changes.

Last month, Microsoft launched an Xbox Live Arcade version of "Doom," the 1993 classic that popularized the first-person shooter genre.

The efforts seem to be paying off. Canessa said Microsoft's data show that those who buy one game — priced from about $5 to $10 — usually end up buying nearly 5 games.

The efforts are not always met with universal praise. Some gamers complain that modern controllers, which sport multiple thumbsticks, triggers and buttons, mean the old games don't feel like they used to.

Although Microsoft is pushing online play as the future of gaming, it has found there are exceptions.

When Canessa's team was working on "Pac-Man," they tried an online feature in which opponents would take turns playing.

"It was really kind of boring to have that over Xbox Live. That was lame," Canessa said.