on paper some of these seem like hacker projects not startups so I would love to see how they see value in these startups.
There isn't any video. If you're curious about one in particular, contact them. They're all stand up folks.
edit: removed google from the above list.
Hacker project:
"Google began in January 1996 as a research project by Larry Page, a Ph.D. student at Stanford.[1] In search for a dissertation theme, Page decided to explore the mathematical properties of the World Wide Web, understanding its link structure as a huge graph.[2] His supervisor Terry Winograd agreed and Page focused on the problem of finding out which web pages link to a given page, considering the number and nature of such backlinks to be valuable information about that page (with the role of citations in academic publishing in mind).[2] In his research project, nicknamed "BackRub", he was soon joined by Sergey Brin, a fellow Stanford Ph.D. student and close friend, whom he had first met in the summer of 1995 in a group of potential new students which Brin had volunteered to show around the campus.[2]"
Asked of previous demo days, and the standard answer has been "no" - probably due to companies not yet ready for release. I thought the purpose of demo day was to allow VC's a sneek look at the latest YC recruits not a general public launch.