Narrative is a Mac OS X native plotting framework written with the Cocoa API. It is already capable (see, e.g., www.trade-strategist.com), but will evolve into a complete OO solution to plotting in Cocoa and GNUStep.
A multi-protocol instant messaging app for Mac OS X
Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.
Watch performance of your stocks on iPhone
The purpose of SNX is to have a modular series of components that report back to a central repository and 'AI' for pattern recognition and anomoly detection. This is to help with IDS systems, and to move to the next generation of security.
StatPaper is a notebook-style front end a la Mathematica or Maple for the R Statistical Environment/Language.
Man's best friend may fetch your paper every morning, but Buddy will fetch a dozen newspapers, clip out summaries of the top stories, stock quotes, sports scores, weather data and comics you want and paste them together into an uber-newspaper.