Tcl (Tool Command Language) is a very powerful but easy to learn dynamic
programming language, suitable for a very wide range of uses, including
web and desktop applications, networking, administration, testing and
many more. Open source and business-friendly, Tcl is a mature yet
evolving language that is truly cross platform, easily deployed and
highly extensible.

Tcl/Tk resources:
  Newsgroup: comp.lang.tcl
  Wiki: http://wiki.tcl.tk
  Books:
   * Practical Programming in Tcl and Tk, 4th Edition
     ISBN: 0-13-038560-3
   * Tcl and the Tk Toolkit, 2nd Edition
     ISBN: 978-0-321-33633-0