http://www.slate.com/articles/news_and_politics/foreigners/2015/06/greek_financial_crisis_will_prime_minister_alexis_tsipras_make_necessary.html

Default, bankruptcy, Grexit, crash: If you feel you’ve read before that these things were about to happen in Greece, that’s because you have. Every debate about Greece’s financial crisis deteriorates rapidly into a discussion of deadlines: repayments, refinancings, meetings of the International Monetary Fund or the European Central Bank. Until now these deadlines have always resulted in further delay. Another one is coming on June 30. That’s when Greece owes $1.7 billion more it doesn’t have.