plt-scheme 4.1.3-1 (amd64 binary) in ubuntu jaunty

 PLT Scheme is an innovative programming language that builds on a rich
 academic and practical tradition.
 .
 It is suitable for implementation tasks ranging from scripting to
 application development, including GUIs, web services, etc.
 .
 It includes the DrScheme programming environment, a virtual machine with
 a just-in-time compiler, tools for creating stand-alone executables, the
 PLT Scheme 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 Scheme,
 ACL2, FrTime, Lazy Scheme, and ProfessorJ (which is a pedagogical
 dialect of Java).