JetBlue on Monday began auctioning off more than 300 round-trip tickets on eBay. Opening bids for the week-end-only flights this month and in October started at a nickel. In addition to the flights, JetBlue also began taking bids for six vacation packages, four of which are "Mystery getaways" packages, that include airfare for two and a four-night stay at a four-star Marriott property at an undisclosed...