Syncless is an experimental, lightweight, non-blocking (asynchronous) client and server socket network communication library implemented in Stackless Python 2.6. It contains an asynchronous DNS resolver (using dnspython) and an HTTP server capable of serving WSGI applications. It aims to be a coroutine-based alternative of event-driven networking engines (such as Twisted and FriendFeed's Tornado). It is already about that fast, but it has fewer features and is less stable now.
Mr Bix is a TCP proxy of sorts in which an incoming connection becomes two outgoing connections, only one of which returns data to the original incoming connection as with a normal TCP proxy; data returned from the other is discarded. It is intended to be used to permit testing of new services or servers with live traffic.