ClearLisp is a Common LISP interpreter written in C# with the purpose of scripting in a .NET or Mono environment. The ClearLisp language supports a large subset of CL and has an object model with generic functions, class and instance methods, properties, and import of existing .NET classes. ClearLisp executes LISP scripts in interactive mode or in Web mode (IIS; XSP or Apache with Mono). Sample ClearLisp code is provided in the form of a personal, file-based wiki Web application.
NTW Lisp is a server written in Common Lisp for applications that use the NTW protocol to communicate with a GUI client. This asynchronous protocol makes it possible to serve remote applications that are indistinguishable from native ones. It's also useful for quickly writing GUI apps from Common Lisp that can be run locally.
ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.
UnCommon Web is a Web application framework. UnCommon Web features a component based UI construction toolkit, template and programmatic dynamic HTML generation engines, and linear (also known as modal or continuation) page flow control. UnCommon Web can sit behind Apache or a pure Lisp Web server.
Etiquette is an interaction protocol construction toolkit. The project's goal is to build a framework for rapid design of network communication code. Etiquette interaction protocols are intended to describe valid communication processes that can occur in networked applications, along with error-handling code. Etiquette provides protocol tracing and single-stepping support.
Allegro Common Lisp is a full ANSI Common Lisp (1994) implementation. It contains many extensions, including 32- and 64-bit native compilation, efficient built-in memory management, foreign functions (for interfacing with other languages), multiprocessing, UNICODE and locale support, XML/HTML parsers, a Web client and server, GTK+ interface (1.2 and 2.0), Java interface, OLE interface (Windows only), profiler, regular expressions, an XML RPC implementation, native Lisp RPC, sockets, DLL and shared library support, and more.