A get-together of econ nerds and business/government leaders that takes place every year in Jackson Hole, Wyoming, a very folksy spot near Yellowstone National Park. The event, hosted by the Federal Reserve Bank of Kansas City, includes discussions and presentations about the economy and new ideas in finance.
It also marks the time when the president of the European Central Bank is most likely to get gored by a bison...if you like betting on that sort of thing.
Markets occasionally respond to the event, since the guest list includes high ranking central bank officials from around the world (including the Fed chair), as well as government finance ministers and executives at major companies. These luminaries will sometimes provide economic forecasts or market insights.
Plus, investors like looking at rich people in jeans.