An experiment in monitoring entropy on Linux machines, here it is in action (click to play):
Build the code like this:
git clone https://github.com/davidsblog/eWeb
cd eWeb
make
You can run the server like this:
sudo ./eWeb 80
Will run the server on port 80. If you already have a webserver running on port 80, you'll need to change to a different port number. When the webserver is running, just use a browser to visit http://localhost:80 (or whatever port you have specified).
You probably don't want to expose this server onto the public internet! It would tell everybody how much entropy your machine has and therefore indicates the quality of random numbers your machine can generate.
I am only using this for experiments and learning.