Suppose someone's given you an application, saying, "Here; this is really
cool.  You should run it on your own computer and see."  If [Tk] was
used to develop the application, and you're unfamiliar with the Tcl/Tk
language, you might not know what's involved in "running it on your
own computer."  Here's an explanation of the minimum you need to know:

You likely don't have Tk installed on your desktop.  It won't take long
to change that, though.  For quickest results, you'll pick a "working
directory" on your desktop, transfer a couple of (kinds of) files
into it, and launch a process.  At that point, the application will be
running.

The two (kinds of) files are
   * the Tk interpreter, and
   * the Tk application source.
Your acquaintance has probably already given you the application 
source, likely named something like 'myprogram.tcl'.  Make sure
you have a copy of that in your working directory.

Now, copy in a working Tk interpreter.  The easiest way to do this
is by choosing the [TclKit] binary appropriate to your operating
system.  You might, for example, retrieve the December 2001 Windows
preview [http://www.equi4.com/previews/tclkit.exe].

At this point, you have a copy of files in your working directory
(or perhaps more; your acquaintance might package his work as a
bundle of several distinct-but-related files).  While at the 
"command prompt" specific to your operating system, move to the
working directory, and enter the command
    tclkit myprogram.tcl
After a few seconds, the program will begin to execute.  That's
all.

myprogram.tcl is likely a "plaintext" source, so you can examine it
with any common editor, and modify it as you choose.  Once you've made
a change, launch an instance of the updated application by repeating
the command
    tclkit myprogram.tcl
at the prompt.










[[Present Tk to those who just want to run an application, and perhaps
tinker with its source, but have no other on-going interest in Tcl.
Point to ActiveTcl and TclKit. Explain how source looks, and how to
invoke.]]