I often like to make UML sequence diagrams. Graphical UML editors are a pain in the butt -- too much mousing around.
I'd rather edit a text file, since I can type really fast. And, then I can source control my text files.
And I found just a tool to do it: Quick Sequence Diagram Editor
This is a nice tool. You edit text in one pane, and it dynamically creates the sequence diagram in the other. Or (although I haven't tried it), you can create the diagrams from command line using text file input.