The beauty of bootstrapping and the joy of JITGeomLab is a simple functional language that we use at Oxford to help school students explore computer programming in a functional language with graphics. Recently, I have been working on a faster implementation that is based on compiling dynamically to code for the Java virtual machine. The project has become self-hosting, in that most of the GeomLab compiler is now written in its own language and compiles itself. The message of this talk is that using the JVM as a target makes it an easy and pleasant task to implement a programming language with reasonable performance, and better fun than ever as a personal programming project. Since GeomLab is open source, it can provide a springboard for your own experiments.