Here is a laptop stand for your bed or your sofa that you can build in 10 minutes. That is, assuming you have the "parts".
My chiropractor has instructed me to stop looking down at my laptop while I'm sitting on the couch. It is bad posture. She insists that I get a table and chair in the living room. Spouse does not approve.
I have looked at a few of the other instructables including the "tables". They look like a lot of work to build. OK, maybe only a few hours... I'm lazy. Also, my wife does not want a big bulky wooden thing to sit around in the living room.
Solution: Twine/Rope/String. 2x Safety pins. One big sofa cushion. 2 knees.
Step 1: Attach Rope to Cushion With Safety Pins.
Attach the string/rope with safety pins to the cushion. Make it tight enough that the laptop sits high. But make sure it is wide enough to sit between your laptop screen.
Step 2: Insert Laptop
Slide the lid of the laptop between the rope and wedge it between the screen and the body. Most laptops have this gap next to the hinges that you can squeeze it into.
If the hinges of your laptop are on the outside of the screen and right near the edge preventing you from stringing it up you could try using velcro on the cushion and on the bottom of your laptop.
Step 3: Lie Down and Work.
Put it on your knees, lie down and work. If it is sitting too high or too low for good posture then just adjust one of the safety pins further back/forward.
Easy to put on and off your knees if you need to get up to the bathroom and keep the heat off your legs too. Might not be so great for ventilation on your computer, but that is not a problem for my mac air.
I actually leave the rope and safety pins on the cushion and wife approves. Simple solution.