According to the Wikipedia, The Mother of All Demos is:
[...] a name given retrospectively to Douglas Engelbart's December 9, 1968, computer demonstration at the Fall Joint Computer Conference in San Francisco. The live demonstration featured the introduction of a complete computer hardware and software system called the oN-Line System or more commonly, NLS. The 90-minute presentation essentially demonstrated almost all the fundamental elements of modern personal computing: windows, hypertext, graphics, efficient navigation and command input, video conferencing, the computer mouse, word processing, dynamic file linking, revision control, and a collaborative real-time editor (collaborative work). Engelbart's presentation was the first to publicly demonstrate all these elements in a single system. The demonstration was highly influential and spawned similar projects at Xerox PARC in the early 1970s. The underlying technologies influenced both the Apple Macintosh and Microsoft Windows graphical user interface operating systems in the 1980s and 1990s.
Watch (switch on subtitles):
- Part 1: introduction.
- Part 2: copy&paste of text.
- Part 4: the mouse.
- Part 8: real-time collaboration.