Multiple Click — select larger and larger subexpressions

, , — enter matched brackets: [], {}, ()

— copy down an input line (Insert ▶ Input from Above)

— copy down an output line (Insert ▶ Output from Above)

— search for help on the name selected, or to the left

— bring up a new instance of the help viewer

— evaluate the selection in place

— copy as plain text

— print selection

— toggle cell groups open/closed

, — open/close all cell groups

— immediately close a notebook without saving

— toggle full screen

File ▶ New — create a new notebook, package, slide show, etc.