A room has n computers, less than half of which are damaged. It is possible to query a computer about the status of any computer. A damaged computer could give wrong answers. The goal is to discover an undamaged computer in as few queries as possible.
(Once again, posed by Gurmeet Singh Manku on his blog)
Highlight the part between the * symbols for the answer.
* [Thanks to Gaurav Bubna for his solution]