Racket (formerly PLT Scheme) is a programming language suitable for implementation tasks ranging from scripting to application development, including GUIs, Web services, etc. It includes the DrRacket programming environment, a virtual machine with a just-in-time compiler, tools for creating stand-alone executables, the Racket Web server, extensive libraries, documentation for both beginners and experts, and more. It supports the creation of new programming languages through a rich, expressive syntax system. Example languages include Typed Racket, ACL2, FrTime, and Lazy Racket.
Unifdef is useful for removing #ifdef'ed lines from a file while otherwise leaving the file alone. You specify which symbols are defined or undefined with -D and -U flags, and unifdef removes the corresponding ifdefs, and the enclosed code if appropriate. It's especially useful for removing those "#ifdef BROKEN" and "#ifdef PRIVATE" clauses from code before you release it. Unifdef acts on #if, #ifdef, #ifndef, #elif, #else, and #endif lines, and it knows only enough about C and C++ to know when one of these is inactive because it is inside a comment or a single or double quote.
Barter is a tool for increasing the quality of applications written in Java. It allows the programmer to use design by contract and define other development aspects right in the classes and interfaces where they are relevant, as JavaDoc comments. It is essentially a code generator for AspectJ, implemented as an xDoclet task.
Dia2Postgres is a Perl script that can be used to convert Dia diagrams into PostgreSQL scripts or PHP mirror classes which can add, update, and modify table entries automatically. It has support for inheritance, simple references (limited to a single field), and a fake enum type which creates a table.
Hat (Haskell Tracer) is a tracing and debugging system for Haskell that can be used for comprehending working programs, and debugging an incorrect one. It consists of hat-trans, which transforms a program into one that traces itself using your normal compiler and a runtime library, and a set of browsing tools that explore the trace after execution of the program has completed.