Make free calls from this web page to anywhere in the USA ... while a computer analyzes your conveersation and pops up web pages, news, images (*ahem*: advertisements) on the web page which are "relevant to your conversation" ... Free, but with a price.
Connect to WebDAV, FTP, Amazon S3, FTPS, or SFTP servers through a virtual drive which is a full file-system drive which works in DOS, PowerShell, etc.
dircproxy is an IRC proxy server ("bouncer") designed for people who use IRC from lots of different workstations or clients, but wish to remain connected and see what they missed while they were away
Amaya has been progressing nicely over the years and supports HTML, XHTML, MathML 2.0, SVG (even transparency and animation), and much of CSS 2 ... You can display and somewhat edit XML ... and there's some powerful tools for live editing...