Here is a window-mounted standing desk that lets you work in a more active fashion at work. The Deskview features an aluminum housing, rubber suction mounts, and 3 tops for you tochoose from. It is rated to hold max load of 120 pounds but you should try to stay under 40 lbs. You can install the desk onto your window in a couple of seconds.
Deskview features a 25 x 15″ work surface. It weighs only 6 lbs.