Here’s a cool DIY on how to use your laptop as a second monitor for your desktop using maxivista software.
It’s really cool as you can expand your desktop across your local ethernet LAN to any other laptops or PCs on it.

Other interesting stuff at Zedomax.com: Consumer, DoItYourself!, ethernet, Graphics, Laptop, LCD, maxivista, microsoft, Misc, multiple_screen, Network, Zedomax