=== To Do
 
  - Documentation of how to use the DSL. 
    - What different things mean
    - How it's constructed
    - Results yielded
  - Generally throw more exceptions, will lead to errors that are easier to fix
  - Odd extra few comments for improving comprehensibility
  - API documentation
  - RubyForge / Google Code / 
  - years_since, months_since, days_since, weeks_since (and, of course, equivalents for until)
  - weeks