More specifically, how do you do the following:
1. Find out if someone can program at all before wasting time on them. I don't want to bring in another candidate that can't FizzBuzz or equivalent.
2. Find if someone is lying on their resume. Do you have any tricks for catching incongruities and probing them?
3. Find out if they will be a drag on the team. Whether that's lack of motivation and output, or sloppy code and bad communication.
1. If you need to understand whether or not they can program, unfortunately you really do need to make them write some code. But don't look at the completeness of the answer. Look at how they're thinking. Get a feel for their understanding of the language. Do they simply know the basics and nothing more? Do they understand how the garbage collector works (if any). These are all means to understand how much he knows, and what his compensation may be.
2. All the good interviews I've had (on both ends) have been simply asking an open ended question about their resume. Ideally something I know about too and let them talk about it. Let them speak until they're done speaking (if they take too long, interrupt them) and then eventually ask them more about it. Drill into his understanding. Don't attack him for it anything, just make him expand more and more. You'll get a good feel of the depth and breadth of their knowledge. The ones who lie on their CV usually ramble, and they become defensive.
3. This unfortunately I've never figured out myself. I've historically let others decide, so I have nothing to say about this.