That said, CareerBuilder was able to identify some out-of-the-box questions that are perfectly legal to ask even if they seem a bit weird – such as the blender question. Because such questions don't discriminate and don't pry beyond the established boundaries of the job interview, and they can elicit important information about whether a candidate is right for a particular job.

Here are some definite no-ask questions:

• What is your religious affiliation?

• Are you pregnant?

• What is your political affiliation?

• What is your race, color or ethnicity?

• How old are you?

• Are you disabled?

• Are you married?

• Do you have children or plan to?

• Are you in debt?

• Do you social drink or smoke?

Lots of HR professionals are aware of this list. Now, let's look at a list of questions CareerBuilder compiled that seem OK but in fact aren't legal to ask a job candidate:

• When do you plan to retire? CareerBuilder notes that asking candidates what their long-term goals are is OK, but asking when they plan to retire isn't.

• Where do you live? This can be interpreted as a way to discriminate based on their location and is therefore illegal. Asking them if they are willing to relocate, however, is OK.

• What was the nature of your military discharge? You can't ask about a military discharge. But you can ask what type of education, training or work experience received while in the military is not.

• Are you a U.S. citizen? No question about citizenship or national origin is OK. But you can ask if a candidate is legally eligible for employment in the United States.

To end on a high note, here are a couple clever questions interviewers have used to size up candidates without violating their basic rights:

• Do you believe in life on other planets? A question like this might be asked to see if a candidate has an attitude that anything is possible.

• What superpower would you like to have? How candidates answer this question can provide insight into how they view their own strengths and weaknesses.

• If you were stranded on an island, which two items would you like to have with you? Answers to this question could indicate a candidate's ability to weather a tough situation with limited resources. Notice the question says "items," thus ruling out people.