Build
docker build -t murer/xvfb-x11vnc-openbox .
Run
docker run -it -p 5900:5900 --name xvfb-x11vnc-openbox murer/xvfb-x11vnc-openbox
Connect
# apt-get install xtightvncviewer
vncviewer localhost:5900
Default password: 123
You can change it here: config/openbox/autostart