Square - The QR code used to pay has the Square logo integrated into it.
GitHub - When looking at a GitHub Contributions streak chart, if the current streak is 0 days, the date range is “Rock - Hard Place”
/via Neil Gupta
Gmail - Incompatible versions of Internet Explorer show a damaged envelope as the favicon.
/via Eric Hansz
Karma - When searching on the infamous “90210” ZIP code, Karma gives the user a quote from its namesake TV show.
/via Patrick H.
Facebook - Offers pirate and upside-down versions of english as language options.
Facebook - The notifications icon shows a different side of the globe depending on your location.
/via Thomas Park
Tehula - The slideshow demo uses names of characters from Lost.