Macopinion has posted a review of the LapWorks Laptop Desk UltraLite, a thinner, lighter-duty version of the company's original Laptop Desk.
Both products fold up to fit in a notebook bag and are designed to provide a stable platform on your lap, as well as a mousing surface. In its fully-open lap tray mode the Laptop Desk UltraLite provides a 22-inch wide workspace. It's 5/16ths of an inch thick, weighs 14.6 ounces, and is available directly from LapWorks for an introductory price of US$19.95.
LapWorks also claims that the UltraLite prevents "hot leg", which we note without puns or innuendos.