Racket (formerly named PLT Scheme) is a general purpose, multi-paradigm 
programming language in the Lisp/Scheme family. One of its design goals is to 
serve as a platform for language creation, design, and implementation. The 
language is used in a variety of contexts such as scripting, general-purpose 
programming, computer science education, and research. (source: Wikipedia)

racket is the command line version, drracket is the GUI-version