I saw only two answers when I started this; both are correct--and literal. Our problem is that you didn't give us a context for the translation.
If the question is informal, you might wish to try a less literal approach, like "¿qué hay de nuevo, viejo?" (literally, "what's new, old man?). This phrase is also used often to translation Bugs Bunny's, "What's up, Doc?"
If you really wish or expect to hear something extraordinary (something that is big), stay with the more literal approach. If you wish to use the phrase as an informal greeting, on the other hand, the less formal approach is probably more appropriate.