I was emailed a set of 10 different "requirements", they were all programming challenges: 4 for #C, 2 for Javascript, 2 for T-SQL and 2 whatever language I wanted. The first four requirements also needed to have unit tests. After spending 6-8 hours of my own time in completing the task very thoroughly and emailing it one morning, a few hours later I got a very unpersonalised email saying "After reviewing your application we decided that your background doesn't exactly match what we are after". This was very frustrating as I really think I solved the problem within the constrains that were presented. My advise would be to only offer this set of requirements if you are convinced about the candidate, otherwise it's a big waste of time, specially when you don't give honest feedback.