Hey there.
It's a fun interview. You will have 2, one may be a student. After each interview session, the interviewers submit their recommendations and the committee reviews and ranks applicants. Make sure you eat before you go, you won't see any food until 6 or so, since they start so late. And be prepared to do some walking - the Texas Medical Center is the biggest in the world, and they'll show you the highlights. I got some ethical/health care questions, but nothing obscure. Each interview is about an hour, pretty standard-type questions about your application.
About the school: TMC is amazing, several of the nation's best specialty hospitals and research institutions, and a huge, and diverse patient base at well, all surrounding 2 medical schools. They'll also tell you about the unique curriculum at Baylor (only 1.5 years basic science, reduced didactic/lecture time, and good deal of PBL - or what they call "IPS") and the neat "extras," like the International Med Track and the Research track programs. Don't worry about being an expert on the school beforehand though - your interviews will be before the tour, and they won't ask you "why baylor?"
Anyways, take it easy in Houston, and enjoy your visit to Baylor. It's a great school.