I was asked to implement an n-way set associative cache. I enjoyed the problem, because it gave me more space from an architecture standpoint than the standard whiteboard-style problem. We were told that our solution could be in c#, java, or python, but c# was heavily preferred. I chose to use c#, the preferred language, which I have no experience in (and was upfront about that fact). We were encouraged to ask questions about the problem, but my only point of contact was a recruiter, who's technical skill topped out at "the third link of googling your exact question." This was a problem, because the recruiter was solely responsible for my hiring decision, and my hiring decision was made based on shortcomings the recruiter perceived that were a result of me being unfamiliar with language-specific idioms, and the recruiter being even less familiar with them.