Hospitality for Russian people is really part of their culture.
When Russian people invite you to their home, for them it's always a special event, a guest coming for a drink, a visit or simply to say hi it's a special occasion, and believe me, they will do everything to make you feel like at home.
When you are guest at a Russian family home, they will offer you everything they have, their warm welcome, food, to drink and they will treat you like a member of the family.
Don't worry if you can't express yourself in Russian, even if they can't speak perfect English, they will make themself understood, without you to be worried about language barrier.
Soon you will realize that for them it's really important a guest in their home and that for them it's really important that the guest always gets the best they have.
They will appreciate a lot if you try to speak just a couple of Russian words, for example when saying "thankyou" or something like that, do that and you will hit the center.
Beside what some people say, Russians are really friendly and don't be surprised if they will cover you in questions about you, your life and your culture.
Russian people are really curious about other cultures, habitudes, etc... and they also have a wide cultulre as well, so don't be worried to ask them about their culture, habitudes etc... you will have a pleasant talk and you will not regret at all their company.
My experience was really really positive, i have been at some Russian family houses and always went back really happy, with new general knowledge and very good impressions.
Thei are really altruist people, and will open their heart in a blink of eye.
Something else you have to know is that when they offer you to drink, you should accept it, otherwise they might get "offended".
Coming from the Western Europe, we are more used to drink coffee, for us coffee is like a cult, part of our culture.
Arriving in Russia, i was really impressed, people don't drink coffee so much, sometimes at all, but they consume liters of tea, and believe me, thea is really a cult, every occasion is good to have a thea, specially for breakfast, lunch and dinner, but as well when you have guests.
Let's spend some words about that.
A samovar is a heated metal container who is traditionally used to heat and boil water in Russia.
Heated water is usually used to make tea, for this reason samovars have an attachment on the tops of their lids to hold and heat the theapot, filled with thea concentrate.
Traditionally is heated with coal / charcoal but inside shops you can find samovars who use electricity to heat water.
In every shop you can find tea, but i don't mean the classic tea in the bag, but concentrated tea.
If you have the chance, buy it, try different flavours and enjoy it with your friends, it's really worth it.