Runescape, 13+ only, Evony/Civony, If you go on, Miniclips or any games site, click on category Multiplayer, and then you may see games, most of them are safe, since most sites, won't post inappropriate material.
If you want to play RuneScape without the chat then there is a tab at the bottom of the chat window. There, you can toggle the chats between On, Friends and Off. Then the chat will stop showing up on screen. To get the chat back, then all you have to do is set it to On.
Online games, chat rooms. I would actually prefer online games, because there is a bigger chance that people are nicer, and plus you get to play games with them, but i guess chat rooms is ok because you don't have to download anything, and maybe its just easier for some people.