In a speech made in May 2013, Varoufakis revealed his thinking wrt defaulting, devaluing and Greece's membership of the Euro.
The "strategy" of Greece's government and (in particular Varoufakis) has baffled many over the past few weeks. However, I have on this site noted that Greece may well not be planning to exit the Euro but instead pushing for Germany to exit it.
The smoking gun, validating this "strategy", has been identified by Zerohedge which quoted Varoufakis's May 2013 speech:
"..If Germany leaves, that is more likely for me, as far as I am concerned that Germany would depart from the euro...".Thus we can see the "strategy" of Syriza, to make Greece so poisonous to Germany (and it certainly is succeeding there) that the Germans will eventually reject Euro membership and walk away.
Thus far the strategy has only succeeded in making Greece poisonous!