ExtendScript is a very powerful tool for adding custom functionality to Abobe products - in my case Photoshop. I've got a non-paid (family) project where I've got to convert a Microsoft PowerPoint file, slide-by-slide into a series of PSDs with lots of little rules: the correct images broken out into separate layers at the correct position and layer level, text combined from all locations in the slide and filled into the correct text layers, layers shown or hidden as needed, and more.