EPUBReader is a free Firefox extension that will let you read ePub files in the browser, without installing additional software! If you click on a link to an ePub-file, you are normally prompted by ::More

Stanza Desktop is a free program that will let you read or convert ePub documents; it will also assist you in transferring your books to Stanza iPhone/iPod Touch. Stanza Desktop currently supports ::More

Zip2Fix is a small, free and portable tool that will let you extract all healthy files from a damaged zip archive, when your regular zip archiver/extractor can not process a zip archive at all, ::More

XenonMKV is a free application that will repackage high-definition H.264/x264 video and 5.1 audio contained in MKV files to an MP4 format that the Xbox 360 can play. No video transcoding required. ::More

If you have a file with a wrong extension or even without any extension at all, and you need to open it, you can try TrIDNet,  a little program that attempts to determine a file’s type using ::More