Daemons provides an easy way to wrap existing ruby scripts (for example a self-written server) to be run as a daemon and to be controlled by simple start/stop/restart commands.
If you want, you can also use daemons to run blocks of ruby code in a daemon process and to control these processes from the main application.
Besides this basic functionality, daemons offers many advanced features like exception backtracing and logging (in case your ruby script crashes) and monitoring and automatic restarting of your processes if they crash.
Physicists have demonstrated a system in which light is used to control the motion of an object that is large enough to be seen with the naked eye at the level where quantum mechanics governs its behavior.
As the old Chinese curse warns, we are living in interesting times.