Howto in Paris from CDG to Paris downtown

I hate to admit that during my years of business, I have completely ignored the public transportation in Paris. From here going forward, this is how I am going to do:
1) Buy a "get to know Paris" ticket at CDG (Charles de Gaulle) to the days that you are going to stay. I bought a 5 day ticket for 48 Euros that covered all zones. This ticket is valid for buses, trains and metro
2) Be aware that public transportation do not communicate to the public in any other language than French, so it is up to you to understand or ask what is going on.

Enjoy Paris, the metro network is awesome and you will save lots of money and headache if you can avoid the Parisian traffic.