Market meltdowns that scorch investors, 100-year floods that occur every 10 years and terrorist attacks such as 9/11.

Nassim Taleb, an author, lecturer and big thinker, calls such unforeseen events "black swans," borrowing from a tale about 17th Century European seafarers who landed on Australia and, much to their surprise, learned that not all swans were white.

Such shocks occur, Taleb says, because even experts fail to consider the likelihood of extreme scenarios. That's why his theory, outlined in his book, "The Black Swan: The Impact of the Highly Improbable," is so intriguing to Chicago's trading community, which seeks to lessen risk by exchanging futures and options. His ideas have earned him cachet with investment bankers as well as rock 'n' rollers.

FUTURES FILE column: Commodity prices soar on foreign growth, weaker ...

Overnight on Wednesday, we received some reassurance that the recent slowdown in the U.S. economy has not leaked into foreign economies. The biggest news came from Japan, where the economy grew at 3.7 percent in the fourth quarter, more than twice as fast as economists had expected.Because Japan's economy is largely export-based, this seemed to bode well for global growth and demand for Japanese goods. The other piece of overseas data came from Australia, where the unemployment rate fell to 4.1 percent, its lowest level since 1974. Then, on Thursday morning, Federal Reserve Chairman Ben Bernanke stated that the Fed was standing ready to lower interest rates further in order to aid U.S. economic growth.Though the Fed has a dual mandate to encourage growth and fight inflation at the same time, it has become readily apparent in recent weeks that the current Fed chairman is focusing much more on growth.

Overview: Oil and gold lead rampant commodities

There was no stopping rampant commodity prices on Thursday as gold marched to a record high for a second successive session, while oil briefly rose above the $100 a barrel level.

Warming to Athens in winter

On Sundays the city's famous flea market spreads this far, where it becomes less of a tourist hotspot and more of a local affair. There are some genuine bargains among the junk and bric-à-brac, but the main appeal is the ambience, with ancient men flogging everything from antiques to knocked-off Rolexes in an atmosphere not unlike an eastern bazaar.

In winter the two-mile pedestrianised ancient promenade that links all of the city's principal archaeological sites becomes an exercise circuit for Athenians, filled with families, dog-walkers, joggers and hand-holding couples. The ancient sites themselves are blissfully free of crowds. Wandering around an Acropolis devoid of noisy visitors, or through the somnolent peace of the ancient cemetery of Keramikos by yourself, is an absolute joy.

GDC Preview

As the Game Developers Conference gets under way this week in San Francisco, GamesIndustry.biz highlights some of the key sessions, announcements, companies and games at the annual business event.

Monday's big draw is Areae's Raph Koster, speaking at the Worlds in Motion Summit. With work on Ultima Online and Star Wars Galaxies under his belt, he's perfect to address "Why Gamers should Care about Virtual Worlds," discussing the growth of online spaces and how they are influencing videogame design.