Httpd.sh is a dumb web server written in Bash. It uses the ctypes.sh plugin to access C socket and file APIs. It uses a single-threaded event loop model. It can serve small files. It does limited error-checking and should not be used in the wild.
$ cd /var/www
$ bash path/to/httpd.sh 8888
httpd.sh: Listening on :8888...
Httpd.sh serves files accessible from the directory it was started in. Note that it is trivial to escape the document root unless you run it in a jail or chroot.
Httpd.sh runs on Linux and FreeBSD using mostly POSIX-standard C APIs (sendfile excepted). It may work on other Unix / near-POSIX platforms with little adaptation.