Recently, I wrote a space invaders game in TCL/TK to learn better how to use the TK canvas, and to practice TCL.
It's a very simply written code, since I've been learning TCL not for a very long time (1 week or so). There is a lot that can be improved by using more appropriated TCL features and libraries.
I posted the game in my blog. Here is the link: http://personalphao.wordpress.com/2012/08/27/376/
You can find screen shots in the end of the post.
The source code (along with the sound and image files) is available in the rar archive I've uploaded to 4shared. Also in that post.