A very long and drawn-out process, involving a quick software test (30 minutes or so) and a much longer programming challenge (a 6-hour deadline).

If those go well, it's followed by a group presentation on your solution to the programming challenge and several individual interviews.

I got lost several times; for instance, after days, I called to see what was going on and received an apologetic reply suggesting I had fallen between the cracks, even though they were apparently very enthusiastic about me as a candidate.

What I found surprising was that there were no particularly hard questions, but bear in mind I am a very experienced engineer.