The last interview I did was for a node.js position. I was told to bring my laptop. When I got there, the put me in an office and handed me a packet with instructions on checking out a nearly empty git repo. Then they said "Write an API that meets as many of the following requirements as possible and push the code. We'll be back in 3 hours."
After 3 hours, I was taken to a conference room where I demonstrated the API. I also talked about a bug I had that had hung me up, but I fixed it right there in the conference room.
Got the offer. It was a great experience. I enjoyed the challenge, but it felt useful and related to the work rather than just esoteric problem that would not likely ever be required by the job, and if it was I'd have time to research it and figure it out.
That actually sounds like a decent way to do things. The only thing I'd change is making it shorter and trying to incorporate some pair programming at least to some minor degree to see how well they communicate along with developing.
In a company that does pair programming, sure, do that, because those of us that hate pair programming would then instantly tell them we're not interested and leave rather than waste time on an interview somewhere we won't want to work.
But likewise, if you're not actually doing pair programming day to day, don't do it in an interview setting.
Erm, okay, I used the wrong terminology. I simply meant two people working on the same project. I didn't mean on the same workstation, that would be terrible.
This, especially if the conference room is filled with a reasonable representation of their programmers, rather than just one or two people, and they get to ask questions and we get to talk about the code.
Hearing someone talk about their own code and explain their approach and the up and down sides of it, is a lot more valuable than simply having the correct answer roll out.
After 3 hours, I was taken to a conference room where I demonstrated the API. I also talked about a bug I had that had hung me up, but I fixed it right there in the conference room.
Got the offer. It was a great experience. I enjoyed the challenge, but it felt useful and related to the work rather than just esoteric problem that would not likely ever be required by the job, and if it was I'd have time to research it and figure it out.