Monitorian - Monitorian is a Windows desktop tool to adjust the brightness of multiple monitors with ease.
Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.
Dimmer - A very small and free utility for Windows to reduce brightness on LCD/TFT screens.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Twinkle Tray - Easily manage the brightness of your monitors in Windows from the system tray.
GnuCash - A personal and small-business financial-accounting software, licensed under GNU/GPL and available for Linux, Windows, Mac OS X, BSD, and Solaris.