Was invited to meet with the PI & a couple of grad students. Everyone was extremely friendly and the interview itself was pretty lax. The whole interview lasted about 20-30 minutes; definitely come with questions, they're here to help you and make sure that this experience is as beneficial for you as it is for them!

One on one in person interview with an HR representative. I was asked general questions about why I wanted to work there and what I hoped to get out of the experience. Also general questions about my resume, nothing too philosophical or especially challenging. My skills were not tested or anything like that. I was only asked questions about fit.