The Laptop Desk is designed to let you work comfortably with a notebook computer on your lap. It costs $24.95, folds into a briefcase, has a mouse rest and features an adjustable rake for easier typing. I can see it being useful in airport terminals.
Check out also the $29.95 PDA Office solution from the same company, which lets you type directly into your docked Palm PDA from your PC. Ideal for entering in that last minute information before rushing to catch that plane. Or whatever.