The process took 2 days. I interviewed at US Bureau of Labor Statistics (Washington, DC) in July 2009
Interview
Applied on usajobs.gov, contacted months later through email. Finally booked an appointment, never received the itinerary of the interview, only received a hand written index card with the name of interviewers after telling them about their failure. Moved from one interview to another, had to find the rooms on different floors. They had me rank the different interviewers. Don't believe all the complements they give you, they are protecting themselves from future competitions. The cubicles were mainly empty.
I interviewed at US Bureau of Labor Statistics (Dallas, TX)
Interview
I had two hour long interviews, the first was more conversational with one interviewer and had more practical questions. The second interview was with two interviewers and more like an interrogation, alternating between the two interviewers with absolutely no conversation. Huge difference in the tones of the two interviews. Second interview questions were more nebulous and behavioral in nature.
I applied online. I interviewed at US Bureau of Labor Statistics
Interview
I applied on the website and received an email a few weeks later to set up an interview. The interview was done remotely and I had two interviewers who were primarily asking personal questions and a few hypotheticals thrown in there.
Very easy interview process. This was for a GS-7 level new grad role so very entry level - may have had something to do with the interviews feeling extremely casual. Mostly behavioral, nothing too out of the ordinary - why bls, strengths/weaknesses, etc. Nothing technical other than asking about basic experiences with data analysis.