uWSGI is a fast, sysadmin-friendly application server container, meant for professional deployment and development of Python, Perl, Ruby and Lua Web applications. It features multiple apps in a single process, advanced logging, sendfile(), memory reports, an integrated profiler, vector based I/O, self-healing, and a lot more.
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.