Fast symmetric cryptography in Javascript
Fossil: Simple, high-reliability, distributed software configuration management ... with bug/issue tracker, wiki, web interface etc.
PyAMF provides Action Message Format ( AMF) support for Python that is compatible with the Adobe Flash Player. It includes integration with Python web frameworks like Django, Pylons, Twisted, SQLAlchemy, web2py and more.
Tornado is an open source [python] version of the scalable, non-blocking web server and tools that power FriendFeed.
The best features of document databases, key/values stores, and RDBMSes in one.
Mongo (from "humongous") is a high-performance, open source, schema-free document-oriented database.
RED checks HTTP resources to see how they use HTTP, makes suggestions, and finds common protocol mistakes.
The Python Google Wave Server
A very good non-PR analysis of Opera Unite.
We're done with the tired old fontstacks of yesteryear. Enough with the limitations of the web, we won't have it. It's time to raise our standards. Here, you'll find only the most well-made, free & open-source, @font-face ready fonts.
A sound level manager that nicely fades applications in and out based on their profile and window focus
Openfire is a real time collaboration (RTC) server licensed under the Open Source GPL. It uses the only widely adopted open protocol for instant messaging, XMPP (also called Jabber). Openfire is incredibly easy to setup and administer, but offers rock-solid security and performance.