
I don’t entirely recommend using this option for a VGA cord, because the cable used by the author the CAT5 ethernet cable is not shielded and doesn’t have the same properties as a native VGA cable. But this solution works too, so if you’re in desperate need of a VGA cord and can run the store an get one, you could approach this instructable.
DIY VGA cord: [Link]

Power over ethernet is a Cisco standard introduced to facilitate the powering of ethernet devices over the ethernet cable. You get the ideea, we try to keep the number of cables down.
This Power over Ethernet step-by-step hack by NYC Wireless member Terry Schmidt shows how to build a simple setup with minimal cost and easy to find components. Pretty simple way to ensure your roof mounted wireless router can get enough juice without running tons of cables through your house.
DIY Power over ethernet (POE): [Via] - [Link]

Zedomax present this really useful project on which you combine a digital thermometer with a Lantronix XPORT ethernet serial device, the result ? you can monitor temperature over the ethernet, from across the globe. You will find full schematics and source codes, everything you need is there in the project.
Ethernet Temperature Monitor: [Via] - [Link]

Want your Arduino to check email? How about sending a twitter (which can then be easily forwarded to a phone via SMS)? Or grabbing data from a website? There are so many possibilites for projects that connect to the Internet to get data, now there’s an easy way to do it with an Arduino.
This shield allows you to add and use an XPort or XPort direct(+) Ethernet module (they cost only US$30-$50) using any 4 pins. All of the TCP/IP stack awfulness is done for you in the module so its super easy to just connect to any server.
Arduino Ethernet (XPort) shield kit: [Link]