A very good discussion with economist Valerie Ramey. I have been familiar with here work for a while, but that's what makes these podcasts so interesting- the ability to hear a lengthy and detailed one on one conversation with some of the best economists in the country.
"Valerie Ramey of the University of California, San Diego talks with EconTalk host Russ Roberts about the effect of government spending on output and employment. Ramey's own work exploits the exogenous nature of wartime spending. She finds a multiplier between .8 and 1.2. (A multiplier of 1 means that GDP goes up by the amount of spending--there is neither stimulus nor crowding out.) She also discusses a survey looking at a wide range of estimates by others and finds that the estimates range from .5 to 2.0. Along the way, she discusses the effects of taxes as well. The conversation concludes with a discussion of the imprecision of multiplier estimates and the contributions of recent Nobel Laureates Thomas Sargent and Christopher Sims."
The references that link from this podcast are very good as well.