This talk will be an introduction to the many wondrous applications of the xy package. We'll focus on creating the "matrix-like" diagrams that constitute the majority of commutative diagrams, and begin to explore the vast range of customization options for such diagrams. Near the end, we'll back off the "matrix-like" assumption and see how you can use Xy-pic to graph functions, draw and glue surfaces, and various other diagrams you usually think you need to go elsewhere to create.