ThinkGeek offers a cool new accessory to pimp your desktop. Make your co-workers look like novice computer users by adding a 7-inch touchscreen next to your big screen monitor.
You can choose between the Mimo 710 USB LCD monitor and the Mimo 740 USB touchscreen LCD monitor.

A single USB connection from your computer gets you an instant high-resolution secondary display. This awesome display is perfect for your IM client, widgets, PC gaming tools, your email, a spreadsheet, your PhotoShop tools, or even video! Not only do these displays enhance productivity, they look great! The single USB connection, combined with a weight of only 1.3 pounds, means the Mimo monitor is ultra portable and cost-effective, as no expensive extra video cards are required.
Features of the Mimo USB monitors include 800 x 480px resolution, 350cd/m2 brightness, 400:1 contrast ratio, USB 2.0, and portrait or landscape positioning.

If you want to use the Mimo 740 Touchscreen version on your Mac, you need to buy drivers for an extra $30.
The Mimo 710 7-inch secondary USB monitor sells for $129.99 and the Mimo 740 touchscreen version sells for $219.99 on ThinkGeek.