What useful applications have we found?

There are a lot of pre-written Tcl applications, that is, applications written in Tcl/Tk or in C using the Tcl/Tk libraries. We use a few of these too:
tkinspect
Fantastic debugging tool for Tk code, a necessity for anyone who wants to write anything ambitious using Tk.
make-a-wish
This handy tool does most of the work for you when building tcl and wish extensions. Juggling makefiles and TclAppInit.c, etc. can be one of the more tedious tasks, and this tool tries intelligently to automate the process.
ical
This is the nicest calendar program I've seen, including those from the
tkmail
If you have users for whom elm isn't easy enough, try tkmail -- it also has enough features to keep the heavy mail users happy. For those who have really huge mail dirs, I have code for a waissearch function from within tkmail (search 100 Mb of old mail in just a few sec).
tkman
It's simple, it's friendly, it makes reading manpages a lot more pleasant, it has all the features I would have thought of and then some.
tclrobots
Officially I don't play games, but I have to praise this one. To win, you must write a better tcl program than your opponents...
xelem
a handy X11 periodic table tool with much useful info available at a click
For a long list of cool Tcl/Tk apps click here