Hi, does anyone have any thoughts on what would be considered good technicaly interviews for new php programmers. Im not meaning the little questions that are intended to know language specific intricacies but more on larger interview questions that potential employees may take an hour or 2 to solve in their own time and then come back with.

Specifically im looking at PHP and object orientated but are there any ideas on suitable problems that a php programmer should be able to solve within a couple of hours?

I am thinking that I want to have demonstrated object orientated techniques and also unit testing capabilities but as for that it can be anything.