Debuggers can seem like dark magic—stopping a running program, tinkering with the program state, casting strange spells on VM internals. I spent much of my career diagnosing problems using “puts” because debuggers intimidated me. If you can relate, this is the talk for you! We’ll use Ruby's powerful TracePoint API to implement a simple but fully featured debugger for Ruby programs. We’ll also explore a few of the advanced techniques behind a "live" production debugger, and discuss some of the debugging features and limitations of the Ruby VM itself.