We describe the Discrete Event Calculus Reasoner, which uses satisfiability (SAT) to solve event calculus problems. The program can be used to perform automated deduction, abduction, postdiction, and model finding. We discuss the architecture of the program and the encoding of SAT problems. We present some simple examples of how the program is used and then present a more complicated example. We discuss the language used to describe commonsense reasoning problems to the program.