wxMEdit, Cross-platform Text/Hex Editor, Improved Version of MadEdit
Precision Trigonometry: Advanced Calculator for Complex Math
IDA Pro plug-in to fix/extract/view RTTI information
a browser based ballistics calculator for arrows and bullets
NfSen plugin to generate and analyze per-IP statistics
Open Source BGP Looking-glass
Simple Cross-platform LaTeX table creator with a GUI and console app.
Very easy to use databrowser and query console for SQLite3 based on QT
a FUSE filesystem for mounting database tables as text files