If you are looking for an exhibition, a film, a book, a talk about any Polish historical topic, have a look at the website of Dom Spotkań z Historią (History Meeting House).
For example, not too long ago they organized a great exhibition of post-war pictures from 1947 by Henry N. Cobb in colour (!) – I must say it really awoke a strange feeling to see the same, destroyed Warsaw of that time in this strange, almost modern way. Some time ago they had an exhibition “Polacy z wyboru” (English “Poles of their own choice”). Most of their projects are accompanied by publications (available for purchase in their shop).
DSH has a wide range of school programmes – not necessarily interesting for visitors, but nice to know that the children are taught a new way of perceiving history – through, for example, urban games. Together with a wide range of all-historical topics and the way they are discussed, this makes this place a must for all people interested in Polish history. The entrance is always free and all exhibitions are translated into English, which is always a good start for Polish history to you.
Until 6 October there is an exhibition about (of course!) conquering the moon as well as about Americans in Warsaw between 1919-1947.