Well apparently my French is a bit rusty.

"Ça va" translates literally to "it goes".

So the above exchange would literally translate to:

    Hello, it goes?
    It goes, and you?
    It goes.

I guess it's no more banal than answering "how's it going" with "it's going", which isn't that uncommon for people to say. Answering "how's it going" with "not bad, yourself?" isn't really any better either.