GNU Artanis – A fast web application framework for Scheme
More seriously, Artanis is written using GNU Guile, one of the best implementations of Scheme language. One day, the folks at GNU were discussing what language they would write the GNU website in - and many chose Python. But I found that strange, because the official extension language of GNU is GNU Guile. And I wondered aloud - why not start a brand new project to provide a web framework written with GNU Guile? To which RMS said, "It's cool, I like this idea." But at that time, it was just an