Spynergy is a pure-Tcl toolkit, created by Steve Wahl and Michael Doyle, which is included with the BOOK Interactive Web Applications With Tcl/Tk.
From the book’s back cover:
“The CD includes the latest releases of Tcl/Tk and the Spynergy® Toolkit, a collection of Tcl/Tk procedures you can use for your own projects. The Spynergy Toolkit gives your applications powerful abilities such as HTML rendering and browsing, creating and managing databases, client/server computing, Web information retrieval, cross-platform file manipulation, and distributed processing. You receive complete instruction on how to use the Spynergy Toolkit to build a Tcl/Tk database, a Tcl/Tk Web browser, a Tcl/Tk Web server, and other advanced Internet applications.”
MDD: It was developed to be compatible with Tcl 7.6 through 8.0, but hasn't been updated since then. The tools all seem to work fine with current versions, though.