Using Lisp Implementation Internals Unportable but Fun

We present a number of developer tools and language extensions that are available for use with Steel Bank Common Lisp, but which are perhaps not as wellknown as they could be. Our motivation is twofold: firstly, to introduce to a developer audience facilities that can make their development or deployment of software more rapid or efficient. Secondly, in the context of the development of the Common Lisp language itself, we offer some observations of patterns of use of such extensions within the development community, and discuss the implications this has on future evolution of the language.