For me it sounds awesome, what do you prefer: working on one real problem in an open source project or working on a fictional white board problem?

Think it lilke this: if you do a whiteboard interview, you have to solve the a problem each time you go to a new interview (loosing time in a problem nobody cares). But if you solve a problem in an open source project you can show it to every company you want to apply (and a lot of people will benefit from your contribution).

I would love this model to be more wildly used.