We study the two-dimensional stochastic nonlinear heat equation (SNLH) and stochastic damped nonlinear wave equation (SdNLW) with an exponential nonlinearity $lambdabeta e^{beta u }$, forced by an additive space-time white noise. We prove local and global well-posedness of these equations, depending on the sign of $lambda$ and the size of $beta^2 > 0$, and invariance of the associated Gibbs measures. See the abstract of the paper for a more precise abstract. (Due to the limit on the number of characters for an abstract set by arXiv, the full abstract can not be displayed here.)