Via google translate from Corriere Della Sera, Beppe Grillo is in favor of a "Referendum on the Euro Within a year"

"Europe needs to be rethought. We consider just one year of information and then hold a referendum to say yes or no to the euro and yes or no to Europe. "Beppe Grillo to ride a strong theme of the last election campaign the 5 Star Movement. "Europe on the euro and the British teach us democracy. No party can claim the right to decide for 60 million people."

"I want to go to Europe and re-discuss a Plan B to be in five years, "added the leader M5S, explaining:" When we do, then we are ready for a referendum and we decide whether to stay in the euro or not."

Sooner or later this sentiment is going to catch fire. And the sooner the better for Europe when it does.

Also see Discussion in Spain on Leaving the Euro; Euro Exit Manifest.