I use a black plastic recycling box tipped on it's side. It's plenty roomy and the heat from the lappy vent keeps it warm inside.
Hee hee, I've ordered a pair of USB powered, heated woolen fingerless gloves for this year.
I should buy a portable USB power supply to go with it so I'm not tethered to the laptop too. LOL
http://www.dealextreme.com/p/usb-hea...ack-pair-30367