Large Scale Structure surveys promise to become the next leading cosmological probe. While simulation is an important and powerful tool (especially at non-linear and shorter scales), it is also important to develop complementary analytic techniques to make precise predictions at large scales. High energy theorists, working on problems from nuclear to Planck scales, have long recognized the power of effective field theories to allow us to concentrate only on the most important dynamics at a given scale, parameterizing away our ignorance of less meaningful details. Fascinatingly, stochastically-sourced classical field theories allow us to apply many of our familiar tools to open problems in precision cosmology. I will introduce the exciting first stages of just such a program: establishing an effective field theory of large scale structure in the early universe.