Most interesting free and opensource software of the month:
VSDC Free Audio Converteris an audio converter that supports many formats (MP3, WMA, OGG, etc…)
iFree Skype Recorder is a Windows program that allows to record Skype calls.
LosslessCut is a free portable cross-platform program that enables you to cut videos in an easy way without quality reductions.
DoubleFilerScanner is a free portable program for Windows that scans selected directories for duplicate files.
Diffinity is a free diff and merging tool for Windows, requires the Microsoft .Net Framework 4.5.1.