Off the top of my head, Pandoc, a tool for converting between different markup/down flavors, and xmonad, a tiling window manager for linux. Both are well known and popular.
Also found it crashed a lot, which I would have hoped would be one of the things Haskell would solve (the problems revolved it having to integrate into C code for linking to X, but that's part of living in the real world).
You can create your own document templates, and tweak the resulting output in a million ways. At my job, I have to create a lot of documentation, often in PDF or docx, and Pandoc has become an integral part of my workflow. I can create documents within the comfortable environment of Emacs, and use Pandoc to produce output in any old format that $pointy_haired_boss may desire.
Complex transformations of data structures are part of the compilation activity too, but they're more difficult to spot in the wild of applications.