Feem - Share files offline. No servers. No cloud. No limits.
EchoWaves - Opensource Social Group Chat written in Ruby On Rails
LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
Shtuff Chat - Free Group / Team chat with persistent history.
Winpopup LAN Messenger - Winpopup LAN Messenger is a cost-effective Office, Corporate, Enterprise Instant Messaging solution.
Anologue - Disposable online chat.