I went through a somewhat difficult interview process about two years ago. The first part was a series of Perl questions that I had to answer within 24 hours .. challenging, but fun. The second part was an hour with the Director, on a shared screen; while he watched, I had to complete four exercises. I think I got two of them done; one of them was with a regular expression that I couldn't get right. It was frustrating for me, and probably not much fun for him.

I understand the Timed Exercise thing -- but I'm one of those people who did poorly on exams (all closed book, in my day), but very well on assignments and labs. I just don't perform well, developing something complex, while someone else looks on.

I prefer the smaller questions when asked in a live setting -- during a session like that, a different interviewer asked me, "And how *else* could you do that?", which was great, because when you're writing code there are lots of ways to get the same thing done, some clearer, and some not so clear at all. At one point I wrote

defined $foo or die "Foo needs to be defined";
[download]

I'm also happy to write something 'within 24 hours', because that's a reasonable facsimile of the work environment. Having to debug a regular expression while a Director looks on is not really representative. IMO.

Good luck with your job search!