The players enact the murder of the king, Act III, scene ii
The players begin to enact the play in full, and we learn that the man who kills the king is the king’s nephew. Throughout, Hamlet keeps up a running commentary on the characters and their actions, and continues to tease Ophelia with oblique sexual references. When the murderer pours the poison into the sleeping king’s ear, Claudius rises and cries out for light.
Link to the full text and information source: "Hamlet," SparkNotes - http://www.sparknotes.com/shakespeare/hamlet/section7.rhtml
Image source: Image source - Circulating Collection, Print and Picture Collection, Free Library of Philadelphia. Subject: "Hamlet" -- Shakespeare.
Original source: Engraved by C. Rolls from a painting by D. Maclise