To celebrate the coming new year, i invite everyone to join our session in Obsidian Conflict. It starts on December 31st 5 AM PST and will last until the vast majority of people are bored.
To run the mod you will need to have Source SDK base 2007 and Source SDK base 2013 Multiplayer installed on Steam. It is preferable that you have Half-Life 2 and Counter Strike Source installed. The mod's site is here: https://obsidianconflict.net/