1. It's a great pattern interrupt.
It's a way to help break the typical habits of those you meet.
It gently brings people back to the present.
People are taken aback by the phrasing of your question. (Slang/Improper English)
2. It helps you to become genuinely interested in other people.
You know the drill. People don't care how much you know until they know how much you care.
3. It's an unusual way of building rapport.
As you know, people's favorite topic of conversation is themselves.
As people talk and you listen it offers you the chance to look for the things you have in common.
4. You're probably the first person that took an interest.
Most people feel more alone than you may realize.
Much of the time everybody's talking and nobody's listening.
People are starving for your attention.
5. Ask the question something like this, "So Bob, what you got going on?"
Remain quiet and do not speak a word after the question is asked.
People are uncomfortable with silence.
Allow Bob a moment to comb the regions of his mind to give you an answer.
If Bob utters some words like, "Nothing" or ": I don't know." your follow-up question is always "Why not?"
6. It's a filtering process.
Based on your subject's answer to the question you can decide how many layers you want to add to the story.
If they're into the same things you're into by all means add the layers. Extend it.
If they're moving in a direction you'd rather not go find a polite way to bring your interaction to a close. End it.
It doesn't take long to arrive at the answer that is most beneficial to all parties involved.
So, what you got going on?