smalltalk is the conversation you're supposed to be having;
The Rundown is the conversation you want to be having.
The basic premise from which all others are derived, that smalltalk should be beaten to death with as many questions as the wielder has to hand. For instance, if your conversational partner mentions that his girlfriend just bought him a humidifier for his apartment, the rules of smalltalk dictate you ask about the humidifier - how big the tank is, if it rotates on its own, if it has variable fan settings. But The Rundown suggests you latch onto the most interesting part of the conversation - the girlfriend. An appropriate followup question to this piece of information would therefore be "Are you in love?"
number two: why chew the fat when you can chew the meat?
An extension of rule one, really. The idea is to ask questions whose answers you actually care about. There's no point prolonging a conversation if nothing is learned about the person you're talking to.
number three: If you can think it, you can ask it.
It stands to reason that the questions whose answers you actually care about are probably not the nicest things to ask, particularly to a passing acquaintences. No question is too raunchy , too inappropriate or too off-the-wall in this scheme. If you have to chose between asking about the random niece's birthday present or what they think she's going to be when she grows up, it's more in the spirit of the affair to ask the more far-reaching question. The questions you ask shouldn't be random (barring one particular question: see below) but they shouldn't be totally obvious, either. Use your imagination.
number four: "how many virgins?"
The mother of all trump cards, designed to keep things moving if all other avenues have been closed to you. Who wouldn't like talking about how many virgins they've slept with after all. It's not supposed to be a mean-spirited question, really, more of a jump-start to more interesting conversational avenues. Hopefully, by the time this question has come up you've been following some pretty irregular conversational patterns and this one won't make you seem too completely off your rocker.
There is also the chance that you'll offend someone, of course, but remember: it's smalltalk with a twist, not grand jury testimony - the long-term effects of these conversations shouldn't be too hard to deal with at all.