Day 17 - Which RPG have you owned the longest but not played?
The RPG that I've owned the longest but have never run or played is the Agone RPG, published in French by Multisim, and then published in a short attempt to sell the game in North America. Based on the novels of Mathieu Gaborit. Agone is set in the land of Harmundia, also known as the Twilight Realms. The game was published in French starting in 1999 by the now-defunct company Multisim, which also translated five books into English starting in 2001. There are over 30 books and supplements for the game published in French.
However, my not running it isn't strictly true. My players actually played a couple of sessions of the game, but decided they couldn't handle the somewhat complicated French designed mechanics, and didn't like the dark nature of the game or the fact that player characters started off as well established characters. It's a game I yearn to run, but alas and alack, never will again.