Because lectures are offered by every department, they are presented in almost every building on campus. However, major lecture series (e.g., the Wilson Center for Humanities and Arts lectures, the Georgia Museum of Art lectures, the Women's Studies Noon Speaker Series) usually meet on a regularly scheduled basis and always in the same location.
Virtually all of the lectures included on the FYO website are free of charge. If a ticket is required, the event description will let you know.
All of the lectures in the various departments are planned and executed by the departments for their students and faculty. You should consider yourself a guest at these lectures and behave accordingly. Many of the lecturers on the website are visitors who are eminent in their fields, and it is a poor reflection on UGA students if people are reading, sleeping, texting or generally not paying attention during their talks.
Arrive a few minutes early.
Almost all lecturers will have a question and answer period at the end of the talk. These can last varying amounts of time, depending on the questions. Unless the lecturer or the person in charge of the event specifically releases you before this time, you should plan to stay for the entire event.