ERA and Swiss citizens can work without any restrictions in Greece.
Citizens of most non-EU countries are required to hold a visa to work in Greece. However, citizens of Antigua and Barbuda, the Bahamas, Barbados, Mauritius, Saint Kitts and Nevis and Seychelles are permitted to work in Greece without the need to obtain a visa or any further authorisation for the period of their 90 day visa-free stay - see the 'Get in' section above for more information.
The Greek government does not recognize 3-year university degrees, and you may have trouble finding work with one in your possession. That being said, work is difficult to find in the country given the current economic situation.
Students from EU countries may enter many sites for free. Students from other countries have their entrance fees reduced. So take your International Student Identity Card with you.
Education in Greece is taken very seriously and it was recently ranked #33 in the Pearson Index of educational attainment. Because of its reputation as difficult and challenging, the country has produced some of the hardest working individuals in all of Europe. Despite this, educational standards are low compared to the European Union, and because of the general difficulty of entering college or university, many Greek citizens choose to study abroad.
For those interested in learning modern Greek, there are several schools offering courses in language instruction for foreigners. Most of these are designed for English speakers, but some schools have courses for people with other first languages. Some schools are in Athens, some in Thessaloniki among them the very good school of Modern Greek language in the Aristotle University of Thessaloniki while others have centres in the islands offering a residential program that combines language study with a vacation. Some offer individual tutoring in addition to classes. Some well established programs are The Ikarian Centre (http://www.greekingreece.gr/), The Hellenic Culture Centre (http://www.hcc.gr/) an associate of The Ikarian Centre, and The Athens Centre (http://www.athenscentre.gr/).