3 stage interview: HR screening, Technical Interview and a Test. The first two stages are easy with questions about culture and the technology you've applied for - my case was Java. The Test is interesting as they give you about 4 hours to complete an algorithm based test that must be written by hand.
The test itself will assess your ability to stay focused on a task for a period of time. It's a bit tough and you can leave the interview with a headache. Personally I don't think it distinguishes good from bad candidates.