I have been doing some interviewing lately, and only just received my first "prototyping" test, based off a short user scenario. It was almost scarily broad, given the 3 days I had to complete it, but I think that's the point -- show initiative, build something cool, be prepared to defend your decisions.

I was personally happy to spend my time doing it, because it was a direct reflection my abilities, and I controlled the result.

I also recently spent a short 2-day stint working with another startup team that was also very instructive. There's no substitute for seeing a team in action, how they approach decisions, collaborate, etc.

I contrast this with the full-day onsite interview I did at one of the old guard dotcoms, which was disorganized, confused, and muddled -- basically, a huge waste of everyone's time. And to cap it off, after I'd had numerous phone calls, in-person meetings, the onsite interview, and bought an SVP lunch (forgot his new bankcard PIN), I got a quick impersonal phone call from HR saying they weren't going to move forward. Needless to say, I agreed.