Some associations...

The Problems:

• One popular example: Bowling Balls and a solution using Perl.
  The article to the solution is in German, but code samples are in English / translation announced.
• Project Euler (a series of challenging mathematical/computer programming problems)

Something from the interviewers perspective:

Joel Spolsky - The Guerrilla Guide to Interviewing.

Monk Wisdom:

• On Interviewing and Interview Questions by eyepopslikeamosquito (with lots of resources)
• Super Search for more...