I must do a quick assessment of dozens of fresh students very quickly. I have 30 minutes meeting with each of them (in two or three days). I want to use most of the time to discuss non technical aspects. So I plan to use 10 minutes for technical questions. The same questions for all of them.

They are all hired already (they are students), what I need to know is the average level in order to prepare a training.

Ideally, the difficulty must be progressive in order to set a level for each. Level I will average, and I'll do an average on each question too.

If you had only 10 minutes and 10 questions to ask to a candidate, what would be your top 10 ?

Three questions, elaborating on the end of Eric Lippert's answer here:

Question 1:


  On a scale of 1 - 10, where do you
  rate yourself in (name the skill
  here)? They answer [n], a number
  between 1 and 10.


Question 2:


  What could you learn from someone at
  level [n+1] ?


Question 3:


  What could someone at level [n-1]
  learn from you?


The most important factor in your decision is to determine where a student (realistically) places themselves, and those three questions will help you to determine that quickly. It also helps identify people that might be compromised by the Dunning-Kruger effect (on either end), but that is another topic.

If anyone can find the reference to this method on SO and edit this post to include a link, I would really appreciate it.

Anyway, that should fall well under ten minutes.
