The other great "adventure" besides the Argonaut journey was the boar hunt. The most famous was the Calydonian Boar Hunt. This one is a bit more difficult in the ancient details, since no epic exists of it. Nevertheless, it is attested as early as the Iliad.
First, all primary sources for it can be found on Theoi. I'll list the main ones.
- Homer, Iliad 9.543ff.
- Hesiod, Catalogue of Women, fr. 98
- Ps.-Apollodorus, Bibliotecha, 1.66
- Ovid, Metamorphoses, 8.269
The point was to kill an oversized boar which was ravaging the land around Calydon. The king, Oenaus, put a bounty out on it, and the most famous Greek heroes of the time (barring Heracles) joined in, including:
- Meleager, son of Oenaus, and the subject
- Castor and Pollux, twin sons of Zeus (though one was said to be born of his mortal father Tyndareus); these two were always adventuring about, and they also joined in the Argonaut quest (they're also the "Gemini" in the sky);
- Jason, leader of the Argonauts as outlined by Yannis;
- Iolaus, most famously known as the side-kick of Heracles;
- Peleus, father of Achilles, the greatest Greek warrior to fight in the Trojan War;
- Theseus, slayer of the Minotaur and hero of Athens;
- Atalanta, with whom Meleager fell in love; also known as the quickest woman in the ancient world, and the only woman ever mentioned in these adventures.
The prime hero of the story is Meleager, and this adventuring ultimately led to his demise.
(Ps.-Apollodorus, Bibliotecha 1.66, translated by Aldrich with emendations by me)
When they had gathered, Oeneus entertained them for nine days. On the tenth day, Kepheus and Ankaios and some of the others refused contemptuously to go out hunting with a woman [i.e. Atalanta], but Meleager...wanted to make a child with Atalanta, and so compelled the men to join the hunt with her. When they had encircled the boar, the animal killed Hyleus and Ankaios, and Peleus accidentally speared Eurytion [king of Phthia] with his javelin. Atalanta was first to hit the boar, in the back with an arrow. Amphiaraus then got it in the eye, and Meleager killed it with a blow on the flank. When he received the skin, he gave it to Atalanta. But the sons of Thestius, who considered it disgraceful that a woman should get the trophy where men were involved, took the skin from her, saying that it was properly theirs by right of birth, if Meleager chose not to accept it. Outraged by this, Meleager slew them and again gave the skin to Atalanta. But Althaea, in grief over the death of her brothers, set fire to the brand [that the Fates declared when consumed would end the life of Meleager, otherwise he would have lived forever], and Meleager died on the spot."
Another variant preserved by Ovid's Metamorphoses is that Meleager instead killed his brothers Plexippus and Toxeus, who were the ones that took it from Atalanta. This makes better sense out of the "birthright" claim.