The first clip shows some old, yet really innovative GUI stuff, taking into account that it was developed in 1963. The guy presenting the Sketchpad is none other than Alan Kay himself:
YouTube – Ivan Sutherland’s Sketchpad.
Also have a look this modern prototype Curve Model sketching application, but don’t be too impressed with how easy it looks – I think it’s pretty difficult, but possible to manage with proper training and a bit of experience:
ILoveSketch from Seok-Hyung Bae on Vimeo.
More on ILoveSketch on http://www.dgp.toronto.edu/~shbae/ilovesketch.htm