This writer seems to think the recent rise in Bitcoin is because of Greek EU exit fears, as citizens flea what they predict to be an unstable banking system. I don't know that I agree with his assessment (he offers nothing to back his claim), but it's at least interesting to note.
If the Grexit fears are behind the recent spike of Bitcoin, then the volumes should be very high in Europe, or that should be the case at least in Greece. However, I have noticed that trade volumes in Europe (and Greece) are lower than the average right now. So in my opinion, something else is behing the recent rise of Bitcoin. May be the talks about legalization in Russia?