Portable Apps - Your Favorite Apps On The Go

If you want to take your favorite applications with you then PortableApps.com is the best software for you to do so. It is completely free and works on any portable storage device so to speak. It is a very lightweight (6MB installed), handy tool to use and has a support of almost all the usual open source software and some compatible freewares.Simply, make every PC feel like your own.

LibreOffice - The Best Open Source Office Suite Available

LibreOffice is a office suite available for Linux, Windows and Mac OS X. It has quickly become a mainstream office suite for Linux users and is still growing, it is available in Ubuntu as a default. It has replaced Open Office at the top of the open source office suites available. It is very simple to use and also has a lot of functions with minimal system requirements. It is not as great Microsoft Office but is worth using as it comes for free and yet powerful too. It is compatible with most of all file formats. It can also be useful to edit PDF's which is a bonus. It also has a fully featured portable version packaged as a portable app so that you can take every documents you have on the go and play with them.

VirtualDub - Opensource Video Capture/Processing Utility for Windows

VirtualDub is a video capture/processing utility for Windows platform. It is a very useful, powerful and lightweight utility for processing linear video streams, including filtering and re-compression. This tool is very useful to compress large videos and also for quick capture and encoding. Different plugin filters further extend VirtualDub's capabilities. 

Greenshot - A Free and Open Source Screenshot Tool

Greenshot is probably the best screenshot tool you'll find for free. It is an open source and lightweight software for Windows with simple and easy to understand features. You can easily capture partial and complete screenshots within a second. Take screenshots - upload it to your blog, show it to your friends, enjoy!