I applied through college or university. I interviewed at Epic (Verona, WI)
Interview
Phone interview with a manager, exams to test creativity and intelligence, on site interview accompanied with a 5 minute presentation on a topic of your choice. It was definitely one of the more involved interviews I've had (out of maybe a dozen) so I would recommend preparing and being on your game. They are looking for bright people that can communicate and learn because schools don't really teach what you will be doing.
Interview questions [1]
Question 1
There is a book called Entertaining Mathematical Puzzles that will give you an idea of the types of questions on the exam that tests your creativity and ability to think outside the box.