Well maybe some people remember videos like Busted, Zombie Rush and many more custom gamemodes.
The community/forum which hosted theese kind of Events are still alive.
Back Than BonerGamerForums (BGF), OfficeRiotForums (ORF) and now they are
called NeXtGenGTA (NGG).
I'm a Event host myself. So if still someone play GTA IV and still playing the Mutiplayer
respectively wanna play the Multiplayer you can join this Friday (17th November 2017)
at 7:15pm CET on http://nextgengta.com
Register and Signup in the thread here:
Would be nice to have some people in the Game like in the old days.
Game: Grand Theft Auto IV
Date: Friday 17th November 2017
Time Conversation Link: Click here
Schedule: Vanilla Modes, Busted, Zombie Rush, Mowtown, DD
Note: if you wanna join this Event you have to register on NGG