ActiveTcl
ActiveTcl is an implementation of Tcl.
Other implementations of Tcl.
ActiveTcl (http://www.activestate.com/activetcl/) is a distribution of Tcl by ActiveState for many common platforms (and is considered to be the standard one on Windows).
Includes both tclsh and wish, as well as many extension packages (notably tcllib, Critcl, SQLite, Snack, tDOM, Img, which are used to solve some of the tasks on Rosetta Code).