They contacted me my senior year of college and offered an interview for a fulltime position, because they had record of my previously unsuccessful applications for internships with them. I was able to skip the phone screens and go straight to the final interview because I had phone screened for the internship position the summer before. The interview itself was four sessions of about an hour each. The first two sessions were programming/math related. Problems like Fibonacci and Pascal's triangle and other common algorithm questions of increasing difficulty. The third one was about object-oriented design and polymorphism. The last one was just a culture fit interview where a few developers take you out to lunch and you just hang out. What really won me over was the positive attitude of all of my interviewers. They never once made me feel pressured, and made it seem like a very learning condusive environment.