Called up for a phone interview. One hour. Not much behavioral at all. Just one very long-winded technical question. It was a very strange question, but the interviewer walked me through it and gave me hints along the way. Overall, the interview could've been handled a little better as far as clarity goes, but it wasn't bad.

There is a stream of incoming tweets, and you have a computer with only enough memory to hold one tweet. How do you return a random tweet, where each tweet has a 1/n chance of being returned? For example, if 5 tweets have come in, then there should be a 1/5 chance of returning any one of those 5 tweets.