Minecraft it's a sandbox game that allow users to create they own gamemodes. For a few years I created and owned a lot of servers. NexusCraft, Lunatium, OceaNet, TempestPvP, EnergyPvP, MineGrech and Glaucus Network.
I got more than 700 online simultaneous players and more than one million registered players.
Grand Theft Auto: San Andreas multiplayer bot
C++ Grand Theft Auto: San Andreas auto driver experiment to make money on a multipler server. It works by reading data from the game's memory. (memory hacking)Source code