Elvis Presley and Marilyn Monroe, both long dead, get new lives in an online game aimed at the 40-and-over crowd that seeks to tap into the Hollywood legends' eternal, and lucrative, popularity.

Presley and Monroe are both starring characters in Entertainment Games' episodic, free-to-play adventures of Retro World, which will launch on Facebook on November 8 before expanding to Google+ and tablet devices.

But in an unusual twist, Presley and Monroe won't play themselves. Just like in Hollywood, they play characters within the serialized point-and-click adventure games.

Entertainment Games is banking on nostalgia and story driven content to connect with the older demographic communing on Facebook and adopting new technology like tablets.

We think the new generation of gamers is the 40-plus crowd, and they don't want games that look like Saturday morning cartoons, said Gene Mauro, president of Entertainment Games,

They want something that appeals to them visually, and has actual gameplay at the core. Story-driven adventure games helped advance the game industry forward 20 years ago, and we believe what is old is new again.

Michael Pachter, video game analyst at Wedbush Morgan Securities, believes as many as half of Facebook's 150 million monthly unique users are over 40 years-old.

The 40-plus audience grows every day, said Pachter. More people over 40 get on Facebook and more people under 40 get older. There is a ton of opportunity in this market.

Pachter noted the games that do best on Facebook, such as Zynga's 'Cityville' and 'FarmVille' and Electronic Arts' 'The Sims Social,' all cater to this audience.

A Pew Research Center Internet and American life tracking survey found the number of early boomers ages 46-55 who used social networking grew from 20 percent in 2008 to 50 percent in 2010. Older boomers, ages 56-64, spiked from 9 percent to 43 percent, and those between 65 and 73 grew from 11 percent to 34 percent in two years' time.

MARILYN MONROE: SPY

In the Owl Files, the first Retro World launch, Monroe plays a 1960s-era spy. Another series features Presley as a doctor -- just as he was in his final film, Change of Habit.

The format allows the stars to appear in multiple games over time as different characters, and both icons will also be available for purchase as custom avatars for players to explore the game world with.

Besides adventure games, players can buy, customize and race classic cars, or join in arcade-style mini-games like Mahjong with friends.

The games all run on the Heyday platform, which allows developers to take licensed images from Spiegel, Corbis and Getty and create interactive experiences in decades ranging from the 1950s to the 1980s.

Entertainment Games has partnered with Dick Clark to serve as the game world's host -- appearing as he did in the '70s -- and also available as a premium avatar. Clark will also deliver content that players can purchase as Retro World expands.

It feels good to be a part of something fun, geared at the 40-and-over community, Clark said.

Imagine being able to revisit your favorite fashion, TV shows, celebrities, cars and more from your teens and 20s. ... I'm excited to be part of the whole Heyday platform, he said.

While Retro World will be free to play, there will be micro-transactions as well as brand-sponsored virtual items to drive revenue for the game aimed at a demographic that spends more money online than any other.

Pachter believes Retro World has a shot at staking a claim in the $2 billion casual free-to-play game arena, half of which Zynga now owns. With that space expected to double to $4 billion by 2013, it will ultimately be the quality of the game experiences that dictate Entertainment Games' success.

And for that, just as they did when they were box office powerhouses, Presley and Monroe have been resurrected to grab the attention of boomer gamers amid a sea of Facebook and online game experiences.

Once they do, watch for more Retro World adventures based on hit television shows from the '50s through the '80s -- with the help, of course, or more Hollywood icons.