The prices of plane tickets go up and down more often than a commuter shuttle. But now there’s Farecast.com, which predicts whether the price of your flight is likely to rise or fall before your travel date and tells you to buy or wait. The site achieves its 70 to 75 percent accuracy rate–high for a market so volatile–by using data mining to analyze past flights and determining which factors most affect ticket prices. The service is available on more than 2,000 popular routes. Free;

From Popular Science Best of 2006