<p>If you want to see a list of classes that will be available during the day and time you're on campus, go to the online schedule of classes here:</p>
<p><a href="http://webster.reg.uci.edu/perl/WebSoc%5B/url%5D">http://webster.reg.uci.edu/perl/WebSoc</a></p>
<p>You can search for classes in a particular major and that meet at certain days. You don't need permission to sit in a class, like YY (that's what I'm going to call yackityack from now on) said, but I would definitely avoid the following courses:
1. Labs
2. Discussions
3. Classes with enrollments lower than 50
4. Classes with course numbers 200 or higher (grad level classes)
5. Anything in the Arts (unless you want to put on a leotard and dance)
6. Anything with an "H" prefix in the course number</p>
<p>If you're interested in IR, there's an Intro to IR course that meets TuTh 3:30-4:50 that has an enrollment of 90, so this might work out for you. All of this can be found at the site I referred you to. Under department name, I picked "Political Science" and then I scrolled down and looked at the titles of the classes until I found one that sounded suitable for your interests. You can also look at courses under the "International Studies" department and see if something sounds interesting. You can do the same for Comp Sci and Comp Lit.</p>
<p>If you sit in on a class, try to sit somewhere where you can make a quick, quiet exit. For example, try to find a set next to an exit door in the back in the aisle. I doubt you'll want to sit through an entire class, so you will want to be able to make a getaway without having to crawl over people in a crowded row of seats.</p>
<p>If you want to talk to faculty, I might stay till the end of a lecture and talk to the prof afterwards. Or, you can go here and find course websites:</p>
<p><a href="http://eee.uci.edu/classes/%5B/url%5D">http://eee.uci.edu/classes/</a></p>
<p>You can click on the department you're interested in and see the different classes that have their websites listed. Often the professors will list their office hours on their online pages, and you can try to find their offices and stop by during the specified hours. If you show up to their office and there are students there, I would probably not bother the prof and let them talk to the students. But if the prof is there by him/herself, you can come in and politely introduce yourself and ask if you can spend a few minutes with them to ask some questions. But if you are going to talk to a prof, speak with confidence and have some intelligent questions prepared. Give them a firm handshake, look them in the eye, and don't say too many "ums" or "likes" when you talk to them.</p>
<p>In terms of campus landmarks to see, I'd definitely try to check out the ARC, like YY and UClippers05 suggested. You can probably ask one of the people at the front desk if they can give you a quick guided tour. I know I did this at UCLA when I told them I was a prospective grad student and they jumped right up and showed me around the Wooden Center.</p>
<p>Definitely take a campus tour. I think they have a couple times each day that they have them. They meet in the Administration Building (I think) and you can probably find out more about tours at the admissions site at <a href="http://www.admissions.uci.edu%5B/url%5D">www.admissions.uci.edu</a>.</p>