You can suggest anything you like in a thread in the 'Suggestions' section of the forum. All suggestions are welcome, just make sure to include details on it :)
Thx!To present your game ideas, just make a thread here, in the suggestions forum, and lay out your game idea cleanly, so it is easy to read. Also, come up with an idea that is completely original, and will be popular on the server. There is not much else to it, but make sure to include details about your game mode.