This is of course a huge topic, but I recently stumbled across a mock-nostalgia page on the Soviet Union, with particular mock-nostalgia for the Stalin era:
"A realm where no kulak goes un-liquidated, no five-year-plan goes un-overfulfilled, and no Great Leader and Teacher goes un-venerated."
Contents of this site can be found here:
Charter of the Cyber-USSR
So, from the period of stagnation:
Moscow University, 1977-1978: Courses on atheism
And from the period of "militant atheism" in the 1920s:
Some anti-religious cartoons and articles in the journal Bezbozhnik (1924, 1927).
There are several links on this page to sample materials in Russian, including covers of this periodical directed against Judaism, Buddhism, Christianity, and Islam. (What, no Hinduism?)
"Militant atheism" in the USSR was crude, and in the Stalin period, became even cruder, with a sledgehammer ideological and instrumentalist approach accompanying "socialist construction". This crudity, accompanying the virtual deification of Stalin, is what a peasant society undergoing crash modernization gives you, a monstrosity the likes of which were not to be seen again until Mao's Cultural Revolution.