Architectural simulators are essential tools for computer architecture and systems research and development. Simulators, however, are becoming frustratingly slow, because they must now model increasingly complex micro-architectures running realistic workloads. Previously, we developed a technique called fast-forwarding, which applied partial evaluation and mermoization to improve the performance of detailed architectural simulations by as much as an order of magnitude [14]. While writing a detailed processor simulator is difficult, implementing fast-forwarding is even more complex. This paper describes Facile, a domain-specific language for writing detailed, accurate micro-architecture simulators. Architectural descriptions written in Facile can be compiled, using partial evaluation techniques, into fast-forwarding simulators that achieve significant performance improvements with far less programmer effort. Facile and its compiler make this performance-enhancing technique accessible to computer architects.