The bloody story of Orestes' revenge on his mother, Clytemnestra, and her lover, Aegisthus, has been super popular for a super long time. (What can we say? People seem to love hearing about seriously messed-up goings-on.) One of the earliest mentions of Orestes' grisly deed pops up in Homer's Odyssey, where it's made out to be a good and honorable act of justice. According to Homer, Orestes' killings are a-O.K. because they avenge the horrible murder of his father.
The tragic playwrights of Athens were all about the story of Orestes and his sister, Electra, and they all took a swing at creating their own version of the tale. Arguably, the most "definitive" version comes from the granddaddy of tragedy, Aeschylus, whose trilogy the Oresteia tells the whole brutal story. The three plays are called Agamemnon, The Libations Bearers, and the Eumenides, and they tell the tale from the murder of Agamemnon to the acquittal of Orestes. These plays make up the only intact tragic trilogy that we still have around. (Yay, for staying power.) The Oresteia is famous for using the myth of Orestes to show how the rule of law and order trumps the primitive tradition of blood feuds and revenge.
Sophocles and Euripides, the other two major players on the tragic team, also did their thing with the myth. They both penned plays titled Electra, which looked at the murder of Clytemnestra more from Orestes' sister's perspective. The two dueling tragedians really put their own stamps on the story and spin the same basic events in different ways. Euripides really had a field day with the myths and wrote several other plays that dealt with its main figures. His Orestes and Andromache both did this, but his most famous one is probably Iphigenia in Tauris, which tells the story of Orestes and his BFF, Pylades, discovering his long lost sister Iphegenia in... well... Tauris.
Modern writers and thinkers have also reinterpreted and used the myth for their various purposes. Eugene O'Neill's Mourning Becomes Electra remixes the Oresteia and places the whole trilogy in post-Civil War New England. Famous existentialist Jean-Paul Sartre uses the myth to explore the burden of choice in his play The Flies. (It's not as complicated as it sounds.) And let's not forget Carl Jung, who furthered Freud's idea of the Oedipus Complex by coming up with the Electra Complex, which theorizes that girls have an innate desire to sleep with their father and kill their mother. (It's more complicated than it sounds.) Even contemporary musicians have been inspired by this myth. Don't believe us? Check out "Orestes" by a Perfect Circle and the album Electra Heart by Marina and the Diamonds.