Machine learning is a discipline that is concerned with the design and development of algorithms that allow computers to evolve behaviors based on empirical data — a fancy name for a simple concept. Behind all the buzzword algorithms such as Decision Trees, Singular Value Decomposition, Bayes and Support Vector Machines lie the simple observations and principles that make them tick. In this presentation, we will take a ground-up look at how they work (in practical terms), why they work, and how you can apply them in Ruby for fun and profit.