In Microsoft Corp.’s wildly successful “Halo” video games, players try to save humanity from aggressive aliens. Now the software giant is getting involving in games dealing with an issue many view as more pressing, if less spectacular: global warming.

Microsoft’s involvement comes amid growing interest in so-called “serious games” that attempt to raise awareness of issues such as energy use, famine or Middle East conflict through video games. The contest is being announced at this year’s Games for Change expo.

As part of that event, Microsoft is sponsoring the “Xbox 360 Games for Change Challenge” in which college students around the world will use hobbyist game-making tools for the company’s home gaming console to make titles based on global warming.

“The goal is to educate and entertain people who play it. There is no specific storytelling, but it will use imagination to try to raise awareness and participation in the issue of global warming,” said Jeff Bell, Microsoft’s vice president of marketing for interactive entertainment.

Microsoft hopes its clout as the world’s biggest software company will spark more interest in such games, which have typically been created by students, aid organizations and independent developers.

“I do believe this is the beginning of a radical new and exciting phase for the gaming industry. This is not going to replace “Halo 3″, it’s not going to replace “The Sims” or “World of Warcraft”, but it will open up more thematic games or even create new genres,” Bell said.

The winner will be chosen in August 2008 and Microsoft promises cash prizes to the best entries. The final winner will also get a chance to intern at the company’s games division and will also have a shot at making the title available to the millions of Xbox 360 owners, who use the console’s online network.

“We wouldn’t rule out trying to provide an environment like Xbox Live Arcade where these games would find their way into the public eye,” Bell said.