SOGo - SOGo is groupware server with a focus on scalability and open standards.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
Baïkal - Cal and CardDAV server
Soulseek - Soulseek® is a unique ad-free, spyware free, and just plain free file sharing application.
Xandikos - Lightweight CalDAV/CardDAV server on top of Git.
Shareaza - Shareaza is the most luxurious and sophisticated file sharing system you'll find.