There's nothing virtual in this Modern Warfare

Plus a piece of modern art is scrubbed away, a ladder demonstration goes awry and more news you can lose.

Real-life violence flared in several US cities this week as Xbox fans, desperate to get their hands on the eagerly awaited eighth episode of the first-person shooter Call of Duty, resorted to tactics they'd doubtless picked up playing the previous versions.

In Kansas City police arrested a teenager who followed a man who had just bought a copy of the game and stole it from him at (real) gunpoint.

In Aurora, Colorado, police said one 31-year-old man who had queued outside his local Best Buy store for a midnight launch-day opening resorted to threats of mayhem when he learnt the game he had ordered was not actually in stock.

The disappointed gamer "threatened to carry out his own version of Modern Warfare at the electronics store," police told the local paper, the Aurora Sentinel.

Officers had been called to the scene after the man threatened to shoot staff and blow up the building. "Fortunately," added the police spokesman, "this situation did not end in violence".

Whoops …

As far as she was concerned she was simply doing her job - removing a stain from the gallery floor where she worked as a cleaner.

Unfortunately, the "stain" in question was part of a modern art installation worth an estimated $1.1 million (Dh4m).

When it Starts Dripping from the Ceiling, by the late German artist Martin Kippenberger, had been borrowed from a private collection by the Ostwall Museum of Modern Art in Dortmund, Germany.

According to a spokeswoman for the city, cleaning staff had been given instructions to stay at least eight inches away from the artwork.

But so convincingly did art imitate life that the hapless cleaner, armed with her scrubbing brush, had no notion that she was tackling anything other than the dried rain puddle that the piece was meant to resemble.

… and whoops again

Had it been intended as a cautionary exercise, then Paul Cavanagh's attempt to climb a ladder could have been considered a success.

Unfortunately for the health and safety official from Gateshead in north-east England, his aim had been to demonstrate how to use a ladder safely for the benefit of the employees of a cleaning firm.

Things didn't start well when Mr Cavanagh forgot to put on his hard hat. One of the watching group threw the headgear up to the instructor, who was already on the ladder, propped against a house.

Mr Cavanagh, who had tied himself to the ladder, let go with both hands as he flailed around trying to catch the hat. Things took a turn for the worse when he and the ladder slipped sideways, over a fence and into a neighbouring garden.

His mortification is now available on YouTube.

As he lies sprawling on the ground, one of his pupils can be heard concluding: "That proves the system doesn't work."

Weight loss - or is it?

It isn't just the euro that's in trouble. Scientists have discovered that the International Prototype Kilogram - a small metal cylinder that has served as the metric yardstick, as it were, since 1889 - has changed weight.

Scientists at the International Bureau of Weights and Measures in Paris have worked out that the cylinder has lost - or possibly gained - about 50 micrograms, equivalent to a grain of sand.

"Actually, we're not sure whether it lost mass or gained it," Alain Picard, director of the bureau's Mass Department, told AFP. "The change may be to due to surface effects, loss of gas from the metal or a build-up of contaminant."