This is a very interesting interview and explains how the Grexit and the many other exits from the Eurozone to come will most likely happen.
The plan makes a lot of sense from a political point of view, as politicians will never allow for a real decline in wages and welfare. Even the case of a dual currency (say Drachma and Euro) is taken into account.
If you have any Euro exposure, you must watch this. The main thing to remember, is that if you have Euros in your account, and your country exists, you lose your Euro. But if you keep them outside of your country, you get to keep them. Be very careful about where you keep your money!