Destroying people with a thought has never been so easy. The other inhabitant of NeuroSky's game-like 3D world collapses, dead, flattened by my psychic powers.

O.K., so it isn't psychic, exactly. It is merely a count of electrical activity in my brain, output by the company's head-mounted brainwave measurer, then translated into virtual physical action. Having taken my turn at the console and wandering for a few minutes nudging cars and sending watermelons flying, I encountered the other "player," who was doing much the same.

"Hey, you can kill her if you like," says Johnny Liu, NeuroSky's Manager of System Applications. "Crush her with a desk."

Feat accomplished, and her avatar respawns at the other end of the map. I go back to flipping, dragging and pushing objects around the game world like a drunken Jedi.

The prototype headgear is hacked into pairs of headphones, and measures baseline brainwave activity, said to provide an insight into states of relaxation and anxiety. The demo setup uses Valve Software's Source Engine--my character is one of the black-clad riot police from Half-Life 2--and the only thing measured by the NeuroSky gear is my level of calmness. Liu continually tells me to remain calm, to calm my thoughts, to think of calm, but all I want to do is crush enemies with desks.

It's hard to describe the experience. I was able to maintain a high level of whatever it actually measured but it didn't seem to be calmness. It was a deliberated mental emptiness that did the trick, such as might be experienced while listening to talk radio. Active concentration, like the kids from Akira, was useless.

"It's like flexing a muscle you didn't know you had," Liu said.

The first toys using the technology will be available soon. Unfortunately, there are no computer game controllers planned: it's a shame, because it made an awesome alternative to Half-Life 2's gravity gun.

"Most physical games are really mental games," NeuroSky Founder Koo Hyoung Lee recently said in an AP interview. "You must maintain attention at very high levels to succeed. This technology makes toys and video games more lifelike."

It's easy to imagine it as a treatment for attention-deficit kids or as a more involved human interface device, but in person, it felt limited, the amazing science behind it notwithstanding. With just a single axis of measurement, for instance, it could only ever be an auxiliary input for a video game.

On the other hand, it's obviously the best thing ever, because I crushed my enemy with my mind. All that is left to do is learn to make an appropriately claw-like grasping gesture when I do so in future.

Click here to Watch a Video of Mind-Controlled Video Games and Machines