Koch recruits at my school, I applied for on campus interviews. It was given by a former alumni who now works with Koch. Expect about 30 minutes of behavioral questions. Like others suggest - google search common behavioral questions and write down some possible responses so you have fresh examples in your head. After the campus interview, I was invited to the Koch headquarters. They invite candidates to Wichita the night following interviews for dinner, and also provide a hotel if you live further away and choose to attend the dinner. They also provided gas compensation for driving. I had 2 interviews back to back, just behavioral questions. Many of the questions were repeated, and I ended up using a lot of the same responses for both interviews.
They suggest that you read 'The Science of Success' before interviewing. I would recommend you at least take a look at Koch's 'Guiding Principles' and '5 dimensions of MBM' before interviewing. When responding to behavioral questions, try to tie in examples that highlight your use of these principles.
Dress nice, follow up, and show that you are passionate about what you are doing. If you take the interview seriously and take the time to prepare, it's not a tough interview.
