I have relatively recently been dropped into the position of being "the technical guy at the interview," and to be honest, I haven't had a lot of luck trying to come up with and use specific technical questions. What I prefer is to just try to get the candidate talking about a project and take the conversation in whichever technical direction seems fruitful.
And then of course every answer leads to more questions: usually "..and why did you make that choice?" :-)
I find a conversation like this is the best way to get a feel for whether they know their stuff or not. It also becomes, I think, fairly apparent when someone is padding their resumé by listing every project that their team or company did, even if they only had a minor involvement. If they can't converse about the project in detail, I assume they weren't deeply involved and that I should probably discount that experience and move on to something different.