I've used Tcl/Tk since about version 7.4. Early on, I encountered a lot of quoting hell, but with the help of Brent Welch's book, I got over it.
Tcl is used as the scripting language in TerraTools, a software product of which I'm the architect.
My only freely available Tcl work is Glossator, a program to assist readers of Latin. The free web page I put it on has since disappeared (I'll have to do something about that), but you can still find it in The Wayback Machine here [1 ]