WASHINGTON -- While Congress has been flaying companies for giving out bonuses while on the government dole, lawmakers have a longstanding tradition of rewarding their own employees with extra cash -- also courtesy of taxpayers.

Capitol Hill bonuses in 2008 were among the highest in years, according to LegiStorm, an organization that tracks payroll data. The average House aide earned 17% more in the fourth quarter of the year, when the bonuses were paid, than in previous quarters, according to the data. That was the highest...