Model-based testing enables the automatic and systematic generation of tests from models of the tested system. While considered by many experts as a breakthrough technology, it is also famed to be hard to apply, and not scalable for real-world applications. Microsoft set out to overcome these obstacles with Spec Explorer 2010, an incubation technology which is available from the DevLabs portal of Visual Studio. Microsoft itself chose Spec Explorer as a cornerstone of the effort to validate open protocol documentation, consisting of more than 200 test suites validating over 40,000 requirements for networking protocols. This breakout session introduces into the basic concepts of model-based testing, demonstrates how Spec Explorer makes them easy to apply, and illustrates the application to projects inside of Microsoft.