calibre is a free and open source e-book library management application.
Convert LRF (Sony BeBB) files to EPUB, PDF, RTF, and HTML. Also converts PDF and DOCX to EPUB.
Convert CSS Snippets to Syntactically Awesome StyleSheets code
Download or convert youtube videos
Tool to convert an addressbook from ldif to vcard
Dawn will convert your address book from one program's format to another.