*Might* be a good time to buy euros, PO (online) offering 1.37 and you might be able to get around 1.40 online elsewhere.
Can't see that Greece could introduce a new currency ovenight and, even if it did, the euro (like GBP) would still be valid for exchange into chocolate buttons.
Hard choice there, I might prefer chocolate buttons to the euro. Mind you, they could be inflationary (on the waistline, at least).