Greek markets are burning again. Is this an opportunity, or a value trap?Well, to start to answer that question, you would need to have an idea of what the value of something is. Greek stock and bond markets are burning again this morning, on the news that payments from the European Union are being delayed to the International Monetary Fund. Apparently the government in Greece is absolutely, completely opposed to reducing spending limits, and it's looking more and more likely that the international banking community is ready to give up on them. Greek bond yields increased by 30 basis points overnight.But that's the government, not the companies.It's important to understand the difference between these things. There are a good number of strong companies that are based in Greece. Many of them have manageable debt levels and maintain profitable businesses. Some of them conduct all of their business in U.S. Dollars. Even if Greek currency was to completely collapse, the equity of these businesses would simply be revalued in whatever currency replaces it. That means you can pick up a whole score of quality banking and oil businesses for ridiculously low prices.ACTION TO TAKE:This cycle has been repeating itself for years. Every time there's a big fat Greek selloff, the markets eventually settle down, and they bounce back. I have traded this over and over, repeatedly walking away with very easy gains exceeding 20% each time. Usually these events were settled within a matter of days or weeks. An easy way to get into their markets is through buying the MSCI Greek Index ETF (GREK).