Russian culture developed under the burden of a series of totalitarian governments, a circumstance that, oddly, supported mathematics education. The Soviet period in particular saw a flowering of mathematical culture, the seeds of which have, since the collapse of the Soviet Union, been carried to the rest of Europe and America. A trickle of ideas, materials--and émigrés--has swollen to a powerful stream. Some of the heaviest influences have occurred in the field of extra-curricular education. We explore some of the ways that Russian and Soviet mathematical culture has fertilized this field. In particular, we look closely at the pivotal role of the professional mathematical communities, both in Russia and in America.