here are a few for the keyboard lover in all of us!
If you type ‘EXPLORER’ in the AutoCAD command line it will open windows explorer.
While in paper (layout) space typing ‘MS’ or ‘PS’ will drop you into or out of a viewport.
Ctrl + R = cycle thru viewports
Hold down the ctrl + tab and cycle thru your layouts
Alt + tab = cycle thru active windows
Ctrl + S = quick save
Ctrl + Q = quit
Ctrl + O = opens a drawing
Ctrl + N = starts a new drawing
Ctrl + P = starts the plot dialog
Using the up or down arrow keys will scroll thru recently used commands
Holding down the shift key will unselect objects
Using ‘U’(undo) will work in most commands.