py-xmlrpc is an extremely fast implementation of the xmlrpc spec for Python (written in C). It supports both blocking and non-blocking clients and servers on Windows and POSIX platforms. Version 0.8.1 is 100% compliant with the xmlrpc validator found at http://validator.xmlrpc.com.
Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).
Cymbeline is an Python application server framework that includes functionality such as database and arbitrary object pooling, Web servers (including SSL), a persistent object repository, and a text console. It was originally designed as an administrative shell for an embedded system, but has since morphed into a more general purpose, run anywhere toolkit.
The Darwin Calendar Server is a standards-compliant server that allows multiple users to collaboratively share calendaring information. It provides a shared location on the network to store schedules, and allows users to send each other and manage invitations. In order to provide interoperability with multiple calendaring clients, the server implements the CalDAV protocol, which is an extension of WebDAV, which is in turn an extension of HTTP.
The BitNami DjangoStack is an all-in-one installer that greatly simplifies the installation of Django and its runtime dependencies. It includes ready-to-run versions of Python, Django, MySQL, and Apache. It supports Linux, Windows, and OS X, so you can share the same Django environment on multiple platforms.