It was only this weekend, of course, that a plan to rescue the Spanish banking system with $125 billion in European funds, news that soothed investors for about five minutes before markets turned back again Spain's government bonds.

With the possibility that the Greek elections Sunday could install the anti-bailout Syriza party in control of the government, a G20 official told Reuters that "the central banks are preparing for coordinated action to provide liquidity":

Wall Street stocks jumped sharply on the news, with the S&P 500 and the Dow Industrials both up more than 1 percent. The euro added to gains and U.S. government debt prices fell, boosting yields.

Separately on Thursday, British finance minister George Osborne said the government and the Bank of England will act together with new monetary policy tools to tackle tightening credit and financial market conditions triggered by the euro zone crisis.

Not that said actions would likely be the last, Reuters points out:

A senior U.S. official cautioned that the Greek election will not provide "the definitive signal on what happens next" in the euro zone debt crisis."

Osborne—author of The Bolter and wife of new Chancellor of the Exchequer George Osborne—left the U.K. on Tuesday to promote her book in New York. When she got on the plane, the prime minister was Gordon Brown. When she got off, it was David Cameron.

She says she spent the trip glued to her in-flight TV—"watching the screen, waiting for new text to emerge." She received a text from her husband shortly after her arrival, as she waited in line at the airport. He hadn't yet been officially appointed, "but he was happy and confident," she recalled.

"Obviously, at the moment, he's quite hard to get ahold of," she said.

Osborne returns to London tomorrow, and she'll spend a week trying to sort out her family's new schedules before returning to the U.S. for another round of publicity. The Bolter (a biography of Osborne's scandalous ancestor, Idina Sackville, out now in paperback from Vintage) seems to have "caught of vein of the imagination" in the U.S, the author says. Americans can't get enough of the escapades of aristocratic Brits. For example, she's heard of several Bolter-themed dinner parties complete with costumes and discussions of the book. Sackville herself was noted for her dinner parties, which generally culminated in partner-swapping.

"I haven't yet heard that a Bolter dinner party that has gone that far," Osborne says, "but my ear is to the ground."