This is a minimal (approx. 1MB) image that runs thttpd (a web server) on port 80. Without any additional configuration it will serve out a single sample page, which makes it useful for testing things like Kubernetes or nova-docker.
If you want to serve your own static content with this image, you can use it like this:
docker run -v /path/to/my/content:/content larsks/thttpd -d /content