A few years ago I thought of a really, really good use for groff and tbl. Thought I'd share.
I write (web-based) business applications. Often I have to generate reports which largely mean PDF files. In the past, I used some open-source PDF generation utilities. They worked, but what a nightmare! Handling paging and lining everything up took hours. Then, a few years ago, I thought of generating groff/tbl input instead and then calling those tools to generate the final PDF output. This made my ability to produce reports skyrocket. I have a deep love of troff but don't get to use it as much as I'd like. Now I'll be using it all of the time. This is a great use of groff et al. I will be using it all of the time now! Blake McBride