Did it take place? Was it legal? Was it underground?
I guess human instinct will always kick in, if so how did it work? Any info would be great 
I’m pretty confident that at least since the 1970s or so, when communist governments somewhat appreciated revenues from tourism, casinos had been established in the touristically important cities in the communist world where foreigners carrying Western currencies could gamble. AFAIK access to those casinos was prohibited to natives (and in any case it would not have been of too much interest to them unless they possessed Western currencies).
There have, however, been public lotteries. In communist Eastern Germany, for example, there was a 5-numbers-out-of-35 lottery established in 1972; cash prizes did not reach the enormous multi-million amounts they can reach in capitalist lotteries (I guess they were capped), but it could win you nice sums and - more importantly in the socialist countries where most people had considerable savings, but the shops didn’t have goods to sell - consumer products.
anyone else?