xkcd substitutions chrome extension
All credit to XKCD.
https://xkcd.com/1288/
https://xkcd.com/1625/
some other xkcd jokes have made it into the newest version. https://xkcd.com/1004/ https://xkcd.com/1418/ https://xkcd.com/1031/ https://xkcd.com/1625/