A page template is a layout of a web page without the content, kind of like a blueprint of a house that outlines the rooms of a house. As a content owner, you can choose a different template for each page of your site.
The academic landing pages are meant to be "stand-alone" landing page that introduce a user to the important content areas of your site. They give the user a large center-top image that can be a slideshow or a single image and 2 to 4 "content buckets" in the body of the page. You can see one in use on the Admissions site.
The 1-3-1 template is a "blog template" with a large center column surround by two smaller columns. It's good for pages that need to house a lot of information. It's used extensively on the College Catalogue site and on the Academic Affairs site. Often, the left column is used as a menu and the right column houses a set of links related to the page.
The 3-2 template is a two column template with the larger column on the left. It's good for pages that need a visual component but don't contain a lot of information. You can't really use a submenu on the two column templates, so they tend to be good for "landing pages" where users jump off to other areas of the site. The 3-2 template is used on the Parents Gateway and the Campus Life landing page.
The 2-3 template is the same as the 3-2 template, but the columns are reversed. The left column is a good place for a series of images. Examples can be found on the Academics landing page or the Multicultural Life page.
The 1-4 template is an excellent way to display a series of pages on a related topic (a sub-site) such as a handbook or other information-centric pages. It has a menu in the left column and a large column on the right. You are looking at an example of a 1-4 template page.