I can't advise you on Chinese (having just done a couple of intro lessons) however I can share some experience in learning Russian.

It's a brute of a language to learn. The alphabet is actually the easiest thing to learn; it's near enough to Greek that many letters are familiar and you'll pick it up with some practice.

Vocabulary is hard, maybe not as hard as a non-European language like Chinese or Arabic, but not as easy as French or German. There are some loan words from other languages (mostly German, French and English) but you will still spend more time memorizing vocabulary than just guessing words. Having said that, many words are made up of common prefixes and combinations, so after a while you'll be able to rely more on context and guesswork.

Pronounciation isn't too hard - not too many sounds different from English - but you'll have to distinguish between "hard" and "soft" sounds, which have a major impact on grammar. Another issue is mobile stress, again with a grammatical aspect. I'll come to these in a moment. Personally I find spoken Russian quite hard to understand - words are elided into each other, a bit like French and unlike, say, German - although my German is very limited compared to Russian, I still find it easier to make out words and structure in spoken German. However I don't have a good "ear" for languages so YMMV.

Now for the grammar. No getting round it, it's a major bitch. Russian has probably the toughest grammar of any language I've learned.

First off, there are a number of grammatical cases, like Latin. However nouns, adjectives and pronouns have quite a high degree of irregularity, so you spend a lot of time memorizing exceptions. Verbs are not so hard but you have to learn the concept of "aspect" (basically, sort of like the perfect/imperfect in French and Spanish verbs, but I'm oversimplifying). Verbs of motion (go, come, etc) have a set of rules again. On top of this there is the aforementioned mobile stress.

For example, "house" in Russian is "dom" (think "domestic"). The genitive is "d'oma" ("of the house") while "houses" is "dom'a". In other words the stress (represented by ') moves forward in the plural. With some words, it moves back, or somewhere else. Same goes with verbs. There are patterns, but no hard and fast rules. This is probably the hardest part about learning Russian.

Russians also distinguish "hard" and "soft" consonsants and vowels and again, grammatical endings are affected by this.

So much for the language, but is it worth learning ? I'm not going to make an economic case - others are more qualified to do so - but I do believe that you should use the opportunity of college to learn at least a few things that aren't completely "practical" - you may not have the time or energy to learn them later and life is not always about practicalities (maybe this is the wrong place to put forward that argument though).

If you learn Russian, first of all as a mental exercise the rigour will do you good ! Secondly you may learn just enough to appreciate the wonders of Russian literature in the native language - Russian has a cadence and beauty of its own, especially the poetry of Pushkin or the prose of Dostoevsky and Tolstoi. Finally, it is a major world language, albeit of a dying empire, and a knowledge of Russian opens up the Slavic world - Polish, Ukrainian, Czech and so forth (I can understand the gist at least of advertisments and newspaper headlines in Czech or Polish).

EDIT: one more point is on expectations. As someone else has pointed out in this thread, college isn't really the place to learn a language, especially in just a semester or two - at best that's a brief introduction. To really master the language you have to spend some time in the country, or at least some time among native speakers (foreign girlfriend, exchange students, immigrant community, whatever). So if you are just looking at a notch on your CV or a distraction from CS, that's fine, but don't expect any great progress in such a short time, especially with a "hard" language like Russian or Chinese.