I interviewed at Microsoft (Redmond, WA) in Dec 2010
Interview
Phone screen and then an in-person interview loop with multiple people. Interestingly I found the phone screen the most difficult compared to the in-person interviews as it it was clear they were looking for very specific answers to their questions requiring me to figure out the right answer versus a possible answer. Not a great way to find good people. The actual interview loop itself was quite good. I found out later many of these phone interviewers are external contractors and not actual Microsoft employees.
Interview questions [1]
Question 1
Didn't find a most difficult question but enjoyed open ended design questions. Be prepared for a few of these.
I applied online. I interviewed at Microsoft (Redmond, WA)
Interview
The process was entertaining but scripted. I found all questions and answers online that allowed me to breeze through their ridiculous questions like "how many bathrooms are in Seattle" and other stupid questions.