my favorite is the GUI. While many credit XEROX with the GUI, most of the ideas came out of the quite amazing Sketchpad by Ivan Sutherland. As an MIT student, this list makes awesome reading!
Here is the relevant snippet:
Nearly 50 years before the iPad, an MIT PhD student had already come up with the idea of directly interfacing with a computer screen. Ivan Sutherland’s “Sketchpad” allowed users to draw geometric shapes with a touch-pen, pioneering the practice of “computer-assisted drafting” that has proven vital for architects, planners, and now even toddlers.
The work demonstrated by Engelbart in his MOD was actually done at SRI, which then inspired XEROX.
When Alan Kay started his PhD at U of Utah, he was given Sutherland's dissertation to start off with (where Sutherland was a professor). That eventually led to his ground breaking Dynapad concept.
Here is the relevant snippet:
Nearly 50 years before the iPad, an MIT PhD student had already come up with the idea of directly interfacing with a computer screen. Ivan Sutherland’s “Sketchpad” allowed users to draw geometric shapes with a touch-pen, pioneering the practice of “computer-assisted drafting” that has proven vital for architects, planners, and now even toddlers.