This by way of Ryan, a former student of mine, currently dating a lovely Russian girl:

Learning a foreign language is difficult. Sometimes it is downright dangerous; like when you accidentally tell your girlfriend that she has a great mustache when you meant to compliment her lips. The difference between губы and усы is noted...

Such little misunderstandings are very common in cross-cultural relationships. Back in 1991 I was dating a woman who had been the national shot-putting champion of Albania. We were in Paris at Cafe Vesuvio not far from Rue de Leningrad, sipping a local red wine whose name I have forgotten, when she looked at me with moist eyes and said, “You have the most beautiful uterus.” Not wanting to spoil the mood, I replied, “Thank you, mon petit chou, my uterus is yours and only yours.” She was visibly moved; no man had ever said such a thing to her before, though doubtless many have since. Alas, our relationship did not last the weekend, and I am left with only misty, water-colored memories...

The Russian word for lip is губа; note the shifting stress in the plural:

The Большой толковый словарь at gramota.ru defines губа like this:

That is about as unromantic a definition as you can find. On a more human level...

I think my favorite Russian word is слизь, which means mucous. Almost all American students will laugh out loud the first time they hear it, which will doubtless mystify Russian readers, so I should explain that English has a word ‘sleaze’ which means a disgusting and dishonorable person, and there is just something in the word that conjures up images of greasy hair and greasy skin and sports coats reeking of stale cigarette smoke that need to be washed much more often. So the association of revolting slipperiness with sleaze and слизь to an American is immediate and visceral. I just love that.

Of course слизь is a perfectly good scientific word, and grammatically it is a feminine third declension noun which declines like this:

English speakers might be surprised to see a plural of the word since we never say ‘mucouses’ in English, but of course in medical and scientific English the proper plural is mucosa. Let's see... what sentences can we come up with without inducing nausea in the reader...

One Russian root word for navel is пуп. That's enough to make any American laugh. And most of us will be so amused that we aren't going to bother to investigate the word further. But here at Russian Word of the Day we pride ourselves on taking interest in all sorts of things that other people simply ignore, and today the belly button is it. It is an end-stressed noun, so it declines like this:

I know, I know: the dative singular made you laugh again.

Anyhoo, пуп is etymologically the source word for navel, one that you will find once in a blue moon in a formal, scientific, or medical context. Thus Russian Wikipedia gives us this info:

But when talking about a person's belly button, the Russians almost never say пуп. Instead they use the end-stressed diminutive пупок.

Sometimes you see belly dancers in movies and you can see their navels, but my mother, who used to take belly dancing classes, tells me that that is a no-no:

Every five or ten years I get into a conversation about the lint that can show up in one's belly button. It seems to be a gender based issue: men have it happen more often than women. Тhe subject was even brought up recently on the web:

One of the amazing things about Russian is that you can make a diminutive of a diminutive, so the dimiminutive of the diminutive пупок is — are you ready for the? — пупочек. This one turns out to be stem stressed:

The word is mostly used to refer to a baby's belly button. There is a bit of a gender difference in the use of this word. Adult men will rarely use it. Mothers and grandmothers will use it more often. (I actually had one Russian man tell me no one used it, but that's simply not true.) For instance, on babyblog.ru I found this little gem:

And as long as we are talking about belly buttons, we should mention the English word omphaloskepsis, which is meditation using the belly button as a focus. That's got nothing to do with Russian. I just really like the word.

Some foods you just can't do without. In the States it's almost inconceivable not to have turkey and mashed potatoes at Thanksgiving, or hamburgers at a picnic, or apple pie for dessert. If those foods aren't part of your life, by cracky, then you just aren't a real American and your status as a patriot is open to question. Among those foods that are inherently Russian, among those foods without which you cannot even conceive of a Russian upbringing and without which you cannot have a Russian soul is… сметана sour cream. The noun is a perfectly regular second declension noun:

American sour cream is not like Russian sour cream. American sour cream is adulterated with thickening agents to make it firm. If you remove the sour cream from its container, it actually retains the shape of the container… for a while at least.

Russian sour cream flows gently and smoothly, creamy and delicious, just like universal love flowing from the cosmic mind. Fresh and almost without preservatives, you eat Russian sour cream right away, not because you are afraid it will go bad, but because it is so wonderful you would never not eat it all. And like universal love, the Russians pour it over over everything: soups, pancakes, meat dishes, fruits, vegetables… Сметана can even be a dish unto itself. The cafeteria at Moscow State University used to sell glasses full of sour cream for direct consumption, some with sugar added, some without, and people just bought a glassful and ate it with a spoon.

And of course, let's not forget the medicinal powers of sour cream, especially in treating sunburn:

Weakness, cough and stuffed nose - we all have experienced these symptoms of the common cold. It ruins your plans and makes it so hard to get out of bed in the morning. Unfortunately, I feel very closely connected to today’s word right now. I cannot wait to get over it!

In Russian, the common cold is called простуда. It is a noun of feminine gender.

The adjective formed from простуда is простуженный.

There are different methods of treating a cold. I can think of a few now that I remember from my childhood. I think the worst one had to do with garlic and onions. First, naturally, you had to eat a lot of garlic and then hold your head above a pot with fresh cut onions and breathe it in. After that the cold would most likely still be there for a few days, but all self-respecting people and/or vampires would choose to stay away...

Here's a cute cartoon that shows other methods we treat the common cold with.