In the late 1950s and early 60s Khrushchev built a massive, modernist, glass and concrete 'palace' for communist party meetings, right within the historic Kremlin. The scale is monumental, with seating for 6,000 people, and not surprisingly the building is not well-liked, given that a considerable part of an older Russian heritage was destroyed to enable its construction.
But I love it. This is not so much because of the building design itself (although there are some fabulously classic Soviet murals) but more about the sheer scale of the whole 'mass' experience. I first visited in the 1970s to see the Bolshi Ballet perform, and was literally swept away; first by the huge crowds pouring down symmetrical sets of stairs to divest themselves of coats; and then by the same crowds moving upwards to the main concert hall itself.
This experience is repeated at the interval; this time everyone surges upwards to the largest room I have ever seen, where buffet-style, these 6,000 people simultaneously snack on Russian champagne and slices of bread and cheese/caviar/meat (at least that's what it feels like). Have visited much more recently, and enjoyed it in much the same way.
I should note that none of my Russian friends and colleagues seem to share this same enthusiasm, nor many of my English workmates; that seeing an event here is not cheap; and that it tends to the extremely popularist - right now they are running Michael Flatley's Lord of the Dance. But, well, to me, attending an event here is still a great way to capture something of the country's Soviet past. The proper post-Soviet name is the State Kremlin Palace (GKD/гкд in Russian), although most people still know it as the Kremlin Palace of Congresses. Moscow-in-your-pocket is an easy place to start to see what's on and this is usually a good site for buying tickets.