Strip the logo and email header/footer crap when printing from Gmail. Nothing more, nothing less.
gmail-pretty-print.js
is the uncompressed source for debugging and poking fun at. You can paste this into the browser console and run it when previewing a Gmail print preview to clean it up.
gmail-pretty-print-bookmarklet.js
is compressed and tested as a bookmarklet that can be saved and accessed directly from the browser bookmark bar for even easier usage. Only tested in Chrome, but might work in other places.