Here's an interesting article about the popular brainteasers in job interviews.

You may find it interesting if you are either looking for a job or interviewing people for a job (or just like brain teasers).

I've actually encountered quite a few brainteasers in job interviews and I enjoy these types of questions. The only problem with these kind of brainteasers is that sometimes interviewers ask questions that have a trick answer.

These trick questions kinda beat the point since either the person has heard the question before and comes out looking like a genius (lucky bastard) or doesn't have enough time to come up with the trick answer and comes out looking stupid.

The trick is to ask questions that show how the candidate thinks, not necessarily the result they come up with.

For a great collection of interview questions (and answers) check out