The International Council of Museums (ICOM) established International Museum Day in 1977 to increase public awareness of the role of museums in the development of society, and it has been steadily gaining momentum ever since. In 2014, International Museum Day garnered record‐breaking participation with more than 35,000 museums hosting events in some 145 countries.
The worldwide community of museums will celebrate International Museum Day on and around 18 May, 2015.
Each year’s International Museum Day theme is proposed by ICOM’s network and aims to promote museum issues within society.
This year’s theme for the event will be Museums for a sustainable society. It highlights the role of museums in raising public awareness about the need for a society that is less wasteful, more cooperative and that uses resources in a way that respects living systems.
Honoured Museum by the Greek Section of ICOM this year is the Industrial Gasworks Museum Gazi (Technopolis Athens), where events will be held from 15-24 of May. The celebration will begin on May 15 with a conference that will have on "Educational activities for the industrial civilization."
Here you may see the events organized from Acropolis Museum and for complete program (in Greek) of the events organized all over Greece you can follow the link.

Acropolis Museum
The Acropolis Museum celebrates European Night of Museums on Saturday 16 May and International Museum Day on Monday 18 May with various activities and events:

Saturday 16 May 2015 - European Night of Museums:
‘Astral divinities: Images, beliefs, cult’
Visitors will have the opportunity to talk with the Museum’s Archaeologist-Hosts about the diverse and fascinating world of the stars and their presence on the monuments of the Acropolis. Evening gallery talks will take place in Greek at 8:30 p.m. & at 10:30 p.m. Participation is limited to 35 visitors per session on a first-in first-served basis (duration: 50 minutes). Registrations at the Information Desk from 8 p.m. onwards.  
European songs with jazz music
The Museum will present in its entrance courtyard at 9 p.m.the Dimitri Vassilakis Quintet which will perform songs from various places in Europe with jazz, swing, latin, blues, fado, r&b and cool music, with the expressive voice of the young singer Sassa Papalamprou.
On this day, the Museum will be open from 8 a.m. until 12 midnight (free entry from 8 p.m. onwards).
Monday 18 May 2015 - International Museum Day:
‘The raven and other winged creatures’
Visitors will have the opportunity to hear from Museum Archaeologist-Hosts attractive stories about ‘The raven and other winged creatures’. Gallery talks will take place in Greek at 10:30 a.m., at 12:30 p.m. & at 6:30 p.m. and in English at 3 p.m. Participation is limited to 35 visitors per session on a first-in first-served basis (duration: 50 minutes). Registrations at the Information Desk from 8 p.m. onwards.  
‘Wings and feathers’ (for children up to 12 years old)
Children up to 12 years old, visiting either independently or as part of a school group, will have the opportunity to discover their favorite winged creature, such as the raven, the owl, the eagle, and also the sphinx, the siren and Hermes. They can meet Archaeologist-Hosts amongst Museum exhibits of the first floor and they can hear from them myths and other beautiful stories about winged creatures from antiquity. Children will then look in the exhibition areas for flying creatures, using their own creation as a guide. Archaeologist-Hosts will expect children from 8 a.m. to 8 p.m. in the Archaic Gallery, next to a relevant signpost. During the activity, supporting material will be used such as sounds, iconographic and written sources on electronic media, as well as material for creation.
On this day, the Museum will be open from 8 a.m. to 8 p.m., with free entry for its visitors.
Commemorative medal dedicated to the raven
On the occasion of this year’s International Museum Day, the Acropolis Museum produced, in collaboration with the Hellenic Mint, commemorative medals dedicated to the raven of the Acropolis. The raven was admired in antiquity for its intelligence and for its ability to guide wayfarers through desert lands, to presage the future through changes in its pitch and flight pattern, and to herald the arrival of rain or the onset of wind with its croaking.