With interest rates hovering at historical lows, it's tougher than ever for banks and thrifts to market their certificates of deposits. Thus many have resorted to special gimmicks and promotions, with the 1992 election season providing the most common theme. Consider:
* Bank of Boston Corp. is running red-white-and-blue ads for its two-year "Washington CD," which is tied to the presidential contest. If voter turnout in Massachusetts exceeds the total of four years ago, Bank of Boston will add 10 basis points to the interest rate. That would bring the current annualized yield to 4.96%.