In Act 2, Scene 2 Hamlet talks to the First Player about a speech he heard before in a play, he starts it off and the Player finishes it. The speech is about Pyrrhus killing Priam in the final battle of Troy.
The rugged Pyrrhus, like th' Hyrcanian beast—
It is not so. It begins with Pyrrhus—
The rugged Pyrrhus, he whose sable arms,
Black as his purpose, did the night resemble
When he lay couchèd in the ominous horse,
Hath now this dread and black complexion smeared
With heraldry more dismal. (II, ii, 438-444)
As hush as death, anon the dreadful thunder
Doth rend the region. So, after Pyrrhus' pause,
Arousèd vengeance sets him new a-work.
And never did the Cyclops' hammers fall
On Mars’s armor forged for proof eterne
With less remorse than Pyrrhus' bleeding sword
Now falls on Priam. (II, ii, 474-480)
Hamlet enjoys this speech so much because it reminded him of the revenge he was trying to seek for his father. Like Pyrrhus, Hamlet was angry about his father’s murder. Pyrrhus fought in the Trojan War because his father, Achilles, had been killed in the Trojan War. Hamlet sees himself as Pyrrhus, because he has been trying to figure out a way to seek revenge on his uncle for the murder of his father. It is essential to understand the story of the Trojan war and the rivalry between Pyrrhus and Priam to comprehend the amount of enjoyment Hamlet seems to have from hearing the Player recite it.