TDDYYΧ is a half-day event to learn new software design approaches and/or new programming languages by mobbing together. To keep being an outstanding Agile programmer, we want to practice more on the fundamentals of software development and design. It is just like training your muscles. Like muscle training, you might find it difficult to continue when you do by yourself. When you are with friends working together, it would be much easier to keep practicing. TDDYYΧ is a perfect format to help you continue practicing. In this session, the presenter will explain how you can run an event, and the results of TDDYYΧ events so far.