Explain is a gem which can explain your Ruby code in natural language as shown below which works only with Rubinius.
The github page is at https://github.com/txus/explain.
Check the example below;
@distance += distance
@hunger += 2
Run explain on the code above
$ explain person.rb
Let’s describe the general attributes and behavior of any Person.
A Person can **walk**, given a specific distance. This is described as follows: its distance will be its distance plus what we previously defined as `distance`. Finally we return its hunger will be its hunger plus the number 2..