On the Spot Interview
Definition: An on the spot job interview takes place either when you apply in-person for a job and you're asked to interview when you turn in the application or when an organization (typically retail or hospitality) announces they will be holding open interviews on a specific date.
When you are applying for jobs in-person, it's important to be prepared for a quick interview to take place as soon as you hand in your application. Be prepared to answer interview questions about your employment history and education, including questions about why you want to work at the company and why you are qualified for the job.
Source: http://jobsearch.about.com/od/jobsearchglossary/g/on-the-spot-interview.htm