Moscow called the date "Night at the Museum"

[Евгений]

The annual cultural event, "Night at the Museum" will be held in Moscow on Saturday, May 14, reported at the Moscow Committee for Culture. On this day, Moscow museums will work with six in the evening until midnight.
Schedule of 2011, thus, was reduced: a year earlier to midnight only worked Moscow museums under federal control, and the city have been opened up to two nights. No other details, including a list of participating museums, the committee is not given, offered to monitor the advertisements in the media.

Simultaneously Mosdepkultura reported that on April 18 and May 18 in the city will be days of historical heritage. These numbers metropolitan museums, exhibition halls, parks and public organizations will work for free. Program of events can be downloaded here (file DOC).
Furthermore, in those days everyone be allowed to see the interiors of buildings usually closed to visitors: banks, public and private institutions, foreign diplomatic missions. Their list is available on the website of the Moscow department of cultural heritage. To visit some monuments will enroll in advance.