Shtuff Chat - Free Group / Team chat with persistent history.
Anologue - Disposable online chat.
EchoWaves - Opensource Social Group Chat written in Ruby On Rails
Tlk2me - Tlk2me is simple real-time messaging platform which is designed exclusively for groups.
JabbR - A chat application built with ASP.NET and SignalR.
Meet in Chat - Meet new people. Have fun sharing photos.