Besides the many other activities, I also try to do a little bit of Mac programming. Current / recent projects include:

OS X projects:

yCal -- a calendaring software. Think of yCal as Apple's "iCal on steroids". In contrast to Apple's calendaring software, yCal supports a nice year view, the ability to mark days with typed markers, and to add notes to days. It sports nicer animated graphics, extensive search capabilities and full OS X calendar store integration. It's a native Objective-C implementation, taking full advantage of Cocoa and all the advanced Lion and Mountain Lion technologies. yCal is publicly available and on sale at www.ycalapp.com since October 2012 under the label of WhizBits.

Clock4X -- an analog desktop clock. Inspired by the brilliant JS Time for the Windows platform, I thought the Mac community might also like a small and decent analog desktop clock. It's almost completely transparent, both for the eye and for mouse clicks. All you'll see are the tick marks and the handles -- which will always stay on top of any other window. Colors and clock size can be configured freely. Try it out -- it's freeware!
 

iOS projects:

Together with a friend of mine, I've also been working on some iOS projects. Most prominently, f/8 (a professional depth of field calculator) and GPSRaw (a GPS tracking app) are being sold under the label Bitwerkz.
 

Older projects:

NvdmAPI -- a native Java API for Novadigm Radia servers. The API runs on any Java 1.2 or above VM and provides full read / write access to the contents of the Radia Configuration Server's object database. In this sense, it replaces the Novadigm Tcl-based API completely.

MoneyWerkz -- a financial management software. MoneyWerkz aims at keeping track of all types of financial-related contracts, providing status reports of your financial situation and calculating forecasts based on user-defined transactions. Implementation is done in Java on MacOS X, based on the native Cocoa API (sorry folks, it's a 'Mac only' app :-). MoneyWerkz was intended to be released as shareware; However, it never really made it to a commercial release because of Apple's discontinuance of the native Java-to-Cocoa bridge.
 

yCal
The Yearly Calendar
Available Q3 2012
for OSX 10.6+

Clock4X
The Desktop Clock
requires OSX 10.5+