Perfect Dark: Source is a Half-Life 2 modification that was started in 2008. Beautifully made, the mod had a large following for some time. Unfortunately, the modification development came to a halt and never resumed. The Gravel Pit hosts the last remaining PD:S server. It’s not perfect, but for those wanting to try out the game, it’s there.
Server IP: 126.96.36.199:9000
*It does not see the server automatically anymore, you must add the server yourself via IP.