gilgamesh
Explanation
The Joke
Two people are reading. One says: "Reading Gilgamesh?" and describes the ancient text: "Epic of Gilgamesh, the oldest surviving great work of literature, where Enkidu and Gilgamesh meet, a prostitute (or priestess) seduces Enkidu and uses all the arts of love." The other person responds dreamily: "They were so like us."
The Humor
The comic plays on the common tendency to romantically identify with ancient or literary figures. One character describes the Epic of Gilgamesh — the oldest known work of great literature from ancient Mesopotamia — specifically highlighting the part where a temple prostitute/priestess seduces the wild man Enkidu to civilize him. The other character's wistful "They were so like us" is funny because it could be read as an earnest literary reflection about the universality of human experience across millennia, but it also implies a very specific and somewhat awkward personal identification with the seduction scene. The humor lies in the ambiguity of whether the reader is having a profound moment of connection with ancient humanity or is just relating to the sex parts.