According to the Orthodox Church, every day of the year has been dedicated to the memory of a Saint or a martyr from the Holy Bible and Holy Tradition. This day carries the name of the Saint and it's called "nameday." If someone is named after a Saint, then there is a big celebration on his/her name day. 
In Greek traditions namedays are usually more important than birthdays. Gifts are given, festive meals and sweets are prepared, and special preparations are made for an open house. Usually, namedays are on the same date, every year. These are the non-floating namedays. 
There are some "floating" namedays though, that every year are on a different date.

Those who are not named after a saint have a party on All Saints' Day, 8 weeks after Easter.

JANUARY

JANUARY 1 - NEW YEAR'S DAY - AGIOS BASILEIOS, VASSILIS (BASIL)
JANUARY 6 - THEOFANIA, THEOFANIS, FOTIS, FANIS, FOTINI
JANUARY 7 - SYNAKSI IOANNOS, IOANNIS, YANNIS, GIANNIS (JOHN), GIANNA, JANNA, JANA
JANUARY 8 - DOMINIKIS (DOMINIQUE)
JANUARY 10 - GRIGORIOS NUSSIS
JANUARY 11 - THEODOSIOS, THODORIS (THEODORE)
JANUARY 17 - ANTONIOS, ANTONIA, ANTONIS (ANTHONY)
JANUARY 18 - ATHANASIOS & KURILLOS, THANASSIS
JANUARY 19 - MAKARIOS
JANUARY 20 - EYTHIMIOS, THIMIOS
JANUARY 21 - MAXIMOS, MASSIMOS/ NEOFYTOS / AGNIS (AGNES)
JANUARY 22 - ANASTASIOS / TIMOTHETOS, TASSOS
JANUARY 23 - AGATHAGELLOS
JANUARY 24 - XENIS, XENI
JANUARY 25 - GRIGORIOS THEOLOGOS / MARGARITA, GRIGORIS, GRIGORIOS (GREGORY)
JANUARY 26 - XENOFONTOS
JANUARY 29 - IGNATIOS
JANUARY 30 - TRION IERARXON
JANUARY 31 - KYROS & IOANNOS AARON

FEBRUARY

FEBRUARY 1 - TRYFONOS
FEBRUARY 2 - YPAPANTI TOS SOTIROS, SOTIRI
FEBRUARY 5 - AGATHIS (AGATHA)
FEBRUARY 6 - VOSKOLOS / FOTIOS
FEBRUARY 7 - PARTHENIOS
FEBRUARY 8 - ZAXARIOS / THEOD. STRATILATOS
FEBRUARY 9 - NIKIFOROS
FEBRUARY 10 - HARALAMPOUS, ZINONOS, HARALAMBOS, HARA, HARIKLIA, HAROULA
FEBRUARY 11 - VASIOS
FEBRUARY 12 - MELETIOS
FEBRUARY 13 - AKULA & PRISKILLIS (PRISCILLA)
FEBRUARY 14 - AYXENTIOS, VALENTINI, ST. VALENTINE
FEBRUARY 15 - EUSEVIOS, EUSEBIOS
FEBRUARY 17 - THEODOROS TIRONOS / POULCHERIAS
FEBRUARY 18 - LEONTOS ROMIS
FEBRUARY 20 - AGATHONOS / VISSARIONOS
FEBRUARY 22 - ANTHI (ANTHEA)
FEBRUARY 23 - POLYKARPOS
FEBRUARY 23 - NESTOROS
FEBRUARY 25 - TARASIOS
FEBRUARY 26 - PORFYROS, SEVASTIANOS (SEBASTIAN), FOTINI

MARCH

MARCH 1 - MARIAS AIGYPTIAS, EFDOKIAS / TIS TYROFAGOS
MARCH 2 - EFTHALIAS
MARCH 3 - KLEONIKOS
MARCH 5 - KONONOS
MARCH 7 - LAURENTIOS (LAURENS, LAURA)
MARCH 8 - THEOFYLAKTOS
MARCH 16 - XRISTODOSIOS
MARCH 17 - ALEXIOS, ALEXIA, ALEXIS (ALEX)
MARCH 18 - KYRILLOS
MARCH 19 - XRYSANTHOS, CHRISANTOS
MARCH 21 - IAKOVOS (JACOB)
MARCH 25 - EVAGELISMOS TIS THEOTOKOS, EVAGELOS, EVA, VANGELIS
MARCH 27 - ILARIONOS, LYDIA
MARCH 31 - YPATIOS

APRIL

APRIL 6 - EFTYXIOS
APRIL 15 - LEONIDAS (LEO)
APRIL 23 - AG. GEORGIOS, GIORGOS, GIORGIS, YORGOS (GEORGE)
APRIL 24 - ELISABET (ELISABETH, LISA, LIES)
APRIL 25 - MARCOS (MARK)
APRIL 28 - PANAYOTIS, PANAGIOTIS, PANOS, PANAGIOTA, PIGI

GIORGOS' NAMEDAY IS ON APRIL 23, UNLESS THIS IS EASTER SUNDAY, OR IN THE WEEK BEFORE IT. 
THEN IT IS CELEBRATED ON THE FIRST MONDAY AFTER EASTER SUNDAY.

MAY

MAY 2 - ZOODOCHOS PIGIS
MAY 3 - TIMOTHEOS (TIMOTHY, TIM)
MAY 5 - EIRINIS, IRINI (IRENE)
MAY 6 - SERAFIM
MAY 7 - AKAKIOS
MAY 9 - CHRISTOFOROS (CHRIS)
MAY 10 - SIMONOS (SIMON)
MAY 11 - KYRILLOS & METHODOS
MAY 13 - SERGIOS, GLYKERIAS, GLYKERIA (SERGIO)
MAY 15 - PAXOMIOS
MAY 17 - ANDRONIKOS
MAY 18 - IOULIAS, IOULIA (JULIA, JULY, JULIE)
MAY 19 - MENANDRIOS
MAY 21 - KONSTANTINOS & ELENIS, KONSTANTINOS, KOSTAS, KOSTATHINA, ELENI (HELEN,TINA)
MAY 27 - IOANNOS ROSOS
MAY 28 - TIS ANALIPSEOS
MAY 29 - THEODOSIAS
MAY 30 - ISAAKIOS (ISAAC)

JUNE

JUNE 2 - NIKIFOROS
JUNE 4 - MARTHAS & MARIAS, MARTHA
JUNE 5 - DOROTHEOS (DOROTHEA, DOROTHY)
JUNE 7 - SEVASTIANIS (SEBASTIAN)
JUNE 8 - KALLIOPIS, KALLIOPI
JUNE 11 - VARTHOLOMAIOS, VARNAVA (BARBARA)
JUNE 19 - PAISIOS
JUNE 22 - ZINONOS
JUNE 29 - PETROS & PAULOS, PETROS, PAVLOS (PETER, PAUL, PAVEL)
JUNE 30 - SYNAKSI TON 12 APOSTOLON, APOSTOLIS, APOSTOLOS

JULY

JULY 1 - KOSMA & DAMIANOS (DAMIAN)
JULY 3 - YAKINTHOS
JULY 7 - KURIAKIS, KIRIAKI
JULY 8 - THEOFILOS, PROKOPIOS
JULY 9 - PAGRATIOS
JULY 11 - EUFIMIAS, OLGAS (OLGA)
JULY 12 - VERONIKIS (VERONICA)
JULY 14 - NIKODIMOS
JULY 16 - ATHINOGENOSS
JULY 17 - MARINAS, MARINA
JULY 18 - AIMILIANOS (EMILE, EMILIE)
JULY 20 - PROFITI ELIA, ILIAS
JULY 22 - MARIAS MAGDALINIS, MAGDALINI, MAGDA, MAGDALENA, LENA
JULY 26 - PARAKSEUIS
JULY 27 - PANTELEIMONOS, PANTELIS
JULY 29 - KALLINIKOS
JULY 31 - IOSIF ARIMATHEIAS, IOSIF, SIFI (JOSEPH, JOZEF, JOOST)

AUGUST

AUGUST 6 - SOTIRIS, SOTIRIA
AUGUST 7 - ASTERIOS, ASTERIA
AUGUST 15 - ASSUMPTION DAY - KOIMISIS TIS THEOTOKOS, MARIA, DESPINA, THESPINA, MARIOS
AUGUST 24 - KOSMA TOS AITOLOS
AUGUST 26 - ANDRIANOS & NATALIAS, ADRIANOS, NATHALIA, NATALIA, NATASHA, ADRIAN
AUGUST 27 - FANOURIOS, FANOURIA
AUGUST 30 - ALEXANDROS, ALEXANDRA (ALEXANDRA, SANDRA, SANDER, ALEXANDER, ALEX)

SEPTEMBER

SEPTEMBER 1 - SIMEON
SEPTEMBER 3 - ANTHIMOS
SEPTEMBER 4 - MOISI, ERMIONIS
SEPTEMBER 5 - ZAXARIOS, ZACHARIAS
SEPTEMBER 8 - GENNISI TIS THEOTOKOS
SEPTEMBER 9 - IOAKEIM & ANNIS (JOACHIM, ANNA)
SEPTEMBER 11 - EVATHIA (EVE, EVA, EVI)
SEPTEMBER 13 - KORNILIOS, ARISTEIDOS, KORNILIA
SEPTEMBER 14 - YPSOSI TOS TIMIOS STAUROS, STAVROS (STEVEN), STAVROULA
SEPTEMBER 15 - NIKITA
SEPTEMBER 16 - EYFIMIAS
SEPTEMBER 17 - SOFIAS, PISTEOS, AGAPIS, ELPIDAS, SOFIA, AGAPI, ELPIDA
SEPTEMBER 18 - EUMENIOS, ARIADNIS (ARIADNE)
SEPTEMBER 20 - EUSTATHIOS, STATHIS
SEPTEMBER 22 - FOKAS
SEPTEMBER 23 - SULLIPSI PRODROMOS
SEPTEMBER 24 - THEKLAS, THEKLA
SEPTEMBER 25 - EYFROSINIS
SEPTEMBER 26 - METASTASI IOANNOS EUAGGELISTOS
SEPTEMBER 27 - KALLISTRATOS
SEPTEMBER 29 - KURIAKOS, KIRIAKOS

OCTOBER

October 1 - Ananios / Pomanos Melodos
October 2 - Kuprianos / Iosstiounis
October 3 - Dionisios Aeropagitos, Dionisos
October 4 - Ierotheos
October 5 - Xaritinis
October 6 - Thoma (Thomas, Tom)
October 7 - Poluxronios
October 8 - Pelagias, Pelagia
October 9 - Iakovos (Jakob)
October 10 - Eulampios
October 15 - Loskianos
October 18 - Loska, Loskas (Lucas, Luke)
October 19 - Kleopatras
October 20 - Artemios / Gerasimos Kefallinias, Yerasimos
October 21 - Sokratous, Sokrates, Sokratis
October 23 - Iakovos (Jacob)
October 24 - Sevastianis (Sebastian)
October 26 - Dimitrios Myrovlitos, Dimitris, Dimitrios, Dimitria (Jim, James)
October 27 - Nestoros
October 28 - Agias Skepis
October 30 - Zinovios

NOVEMBER

November 1 - Ag. Anarron/Kosma & Damianos, Anargiros, Argiris, Kosmas, Damianos (Damian)
November 8 - Mixael & Gavriel, Mixalis, Michail, Michali, Michalis, Mike, Angelos, Stamatis, Stamos (Michael, Angelo, Gabriel)
November 9 - Nektarios
November 11 - Mina / Viktoros (Victor, Vic)
November 13 - Ioannos Xrysostomos
November 14 - Filippos, Philippos (Philip)
November 16 - Mathaios, Mateos(Matthias, Mat)
November 18 - Platonos
November 21 - Eisodia tis Theotokos, Despina, Maria (unmarried)
November 22 - Filimonos (Filemon)
November 25 - Merkourios / Aikaterinis, Katerina (Catherine, Cathy, Kathy, Kate, Cait, Karin)
November 26 - Stulianos, Stella, Stelios, Stylianos
November 27 - Nathanail
November 30 - Andrea, Andreas (Andrew, André)

DECEMBER

December 1 - Theoklitos
December 2 - Muropis
December 4 - Varvaras, Barbara
December 5 - Savva, Savas, Diogenes
December 6 - Nikolaos, Nikos (Nicolas, Nick, Niek)
December 7 - Amvrosios, Ambrosius
December 9 - Agias Annis, Anna
December 12 - Spuridonos, Spiros
December 13 - Eustratios / Loskias, Stratos, Stratis, Lukia
December 15 - Eleutherios, Elefterios, Lefteris
December 17 - Daniel / Dionysios Zakunthos, Dionysos
December 18 - Sevastianos & Zois (Sebastian, Zoe)
December 19 - Aglaias
December 20 - Ignatios
December 21 - Themistokleous, Ioulia, Julia, Julie
December 22 - Anastasias, Anastasia
December 24 - Eugenias, Evyenia, Efgeni, Jefgeni, Yefgeni
December 25 - Christmas Day, Christos, Chrisa, Chrisanthi, Christina
December 26 - Emmanouil / Synaksi Theotokos, Manolis, Manuella, Emma
December 27 - Stefanos, Stephania (Steven, Stephan, Stefania)