I've mentioned two weeks ago that Google started to label pages that include search results. For some of these pages, Google's snippets now use lists, so you can distinguish between separate items. These snippets are twice as big as the regular snippets (4 lines vs 2 lines) and they include useful information like prices or dates.
Sometimes Google is confused and shows similar snippets for blogs, especially if homepages look like search results pages.
Google's snippets usually include one or more excerpts from the page that include some of your keywords and are separated by ellipses.
Update: It's official. "If a search result consists mostly of a structured list, like a table or series of bullets, we'll show a list of three relevant rows or items underneath the result in a bulleted format. The snippet will also show an approximate count of the total number of rows or items on the page," explains Google.