Some call it a high-tech version of tag. Others say it's the modern day equivalent of hide-and-seek. Paintball has only been around since the 1980s, but more than 10 million people of all ages now play it worldwide.
If you haven't played, it's pretty simple: players hunt their opponents, take aim, and splatter them with paint-filled "bullets." it all makes for a fun and competitive afternoon. It's also safe, thanks to the protective gear players are required to wear.
Paintball is one of the fastest growing sports in the U.S., with everyone from church groups to young Republicans getting together for fun-filled weekend outings. But some radical Islamists are using paintball for a far more sinister purpose: as a training ground for jihad.
"They're using paintball for paramilitary training," said Jeffrey Epstein, president of America's Truth Forum.
America's Truth Forum is an anti-jihad organization. Along with terrorism analyst Laura Mansfield, Epstein has been tracking what he calls a disturbing trend among Islamists.
"They're tying paintball into a larger, more grand-scale mission.they're using it to network and bring other Muslims together for communication and to indoctrinate," Epstein explained.
Mansfield supplied CBN News with an al-Qaeda tape posted on a Muslim message board in the U.S.
It begins with images of missiles taking out America, then moves on to a speech by Adam Gadahn, an American-born member of al-Qaeda.
Next come scenes of two men playing paintball. But that's not all. The men also conduct mock suicide bombings, and practice explosives training.
But most of the footage shows them playing paintball, until the video ends with this chilling message: "Feel the rush! High speed paintball!" and then more images of missiles hitting America.
Epstein said, "It shows a tie. It's as if al-Qaeda put this thing together to get the message out to their citizens or their followers on how to train using paintball, and what's expected of them."
If that is the case, jihadists are listening. One of the London subway bombers, Mohammed Khan, was an avid paintball player. Likewise, 17 Toronto Muslims charged this summer with plotting terrorist attacks in Canada used paintball to train.
"The CSIS, which is the Canadian equivalent of the FBI, is starting to investigate who's playing paintball in Canada," said Epstein. "Because they know that there's a tie between paintball and some of the terrorists they've picked up."
Another Canadian Muslim charged with planning terrorist attacks, Mohammed Khawaja, played paintball. Here in the U.S., two Georgia Muslims charged earlier this year with plotting attacks against U.S. targets played as well.
The most notorious case occurred in the Washington, D.C. area. A group of 11 American Muslims there have been convicted for plotting to wage jihad against U.S. troops in Afghanistan and Indian troops in Kashmir. They trained by playing paintball in the northern Virginia countryside. One of the men told a grand jury he considered paintball a form of jihad.
U.S. Attorney Chuck Rosenberg worked on that case.
He said, "We had some information that this was a group that wanted to engage in jihad, violent jihad, against U.S. interests and allies."
Rosenberg says he's played paintball with friends, and that it's perfectly safe and legitimate.
"I don't think anyone needs to be concerned about the fact that people play paintball. It's an innocent sport," he said.
But he warns that, like anything, it can be misused.
Rosenberg said, "The military trains using paintball. Law enforcement trains using paintball. So the fact that bad guys might play paintball as well is not terribly surprising."
Dr. Mohammed Alo runs Paintball Times, the largest paintball Web site in the United States. Alo, a Muslim, has been playing paintball since he was a teen.
"If you notice the terminology we use, we don't call them guns, we call them markers," Alo said. "We don't call them bullets, we call them paintballs. And there was a really strong movement during the early 90s to get away from the military/warfare-type terminology because we don't want kids and people growing up saying, 'Oh, I shot somebody.' No, you didn't shoot him. You marked him. You eliminated him. You didn't kill him."
Alo says paintball is just a game, and that it's nothing like real warfare.
"If you're using paintball to train for some kind of military activity or some kind of terrorist plan, then your plan is most likely gonna fail. And I would consider these people idiots," Alo asserted.
But Epstein said paintball may be the next best thing.
"Paintball is a relatively inexpensive way to target practice," Epstein said, "as opposed to spending a larger amount of money on securing modern weaponry and ammunition."
He points to this ad from the Muslim American Society, or MAS, calling on "serious manly brothers" to play paintball. A 2005 Chicago Tribune article called MAS the American arm of the Muslim Brotherhood-- a worldwide jihadist movement.
Another American Muslim group, the Muslim Students Association, has sponsored several paintball outings. The group's online publication has called paintball an "excellent way to learn about combat."
The Muslim Students Association was founded by the Saudi government. It's active on campuses throughout the United States and Canada.
Alo has spoken at Muslim Students Association events. He says they're not radical. Epstein says otherwise. He cites one of the group's recent gatherings as an example.
There was a huge conference that was hosted in part by the MSA and Siraj Wahajj, Epstein recalled. "I happened to speak there," he said. "Now, he's an indicted co-conspirator in the World Trade Center bombing, according to the U.S. attorney's office."
With a number of American Muslim groups sponsoring paintball outings, and several paintballers arrested for terror plots, should the U.S. government monitor who's playing paintball? Opinions vary.
Alo said, "If we were to try to find every person that's playing paintball that's also Muslim, obviously we'd have a huge task at hand. Because I'm guessing a lot of people play."
"We've been watching this for a while. We are in danger," warned Epstein. "I would hope that the government, our law enforcement agencies, will take more of an in-depth look at what's taking place here."
The U.S. attorney we spoke to said the government doesn't have the time or money to monitor who's playing paintball. He said the overwhelming majority of people who play don't have bad intentions. As for the minority that does? Dealing with them won't be a game.