This is essentially what we do. Write a program to fetch some data from S3 using these credentials we made you, perform some analysis on them (algorithm questi

This is essentially what we do. Write a program to fetch some data from S3 using these credentials we made you, perform some analysis on them (algorithm question, generally with recursion) and then display the final output. And write a test for it. We provide a stubbed-out Rails project on Github so they don't have to know all the details about S3. With this we test three things: 1) Can they quickly find missing info on Google/Stack Overflow (S3 stubs) 2) Can they handle recursion? (Algorithm question) 3) Can they write a test? Then we go over their submission on Skype. It's worked pretty well for us.