Besides building the entire website from the ground up as a custom Rails application, one of my personal proud achievements for the project is something visitors never see.
Scratching my own itch, I build a blog posting view which provides raw HTML input with a syntax-highlighted editor. I find WYSIWYG editors finicky and the code they produce messy. Since the whole team is proficient in basic HTML, this made a lot of sense for us.
To help the mental translation of HTML to a visual representation, I included a live preview which inserted the HTML as it was edited into the blog template.
The previous versions of this website were based on WordPress, and the old blog posts were scattered over several databases. I wrote scripts and parsers to consolidate all these posts into the schema created for the new site and ensured all encoding issues were dealt with.