I bought a small desk so I could work in bed and on the couch. It came pre-assembled and is sturdy. I can adjust the height and angle, and it has rubber stops along the bottom edge to keep my computer from sliding off. It's much more comfortable than resting my laptop on my thighs.
Put it on a regular desk and now you have a standing desk.
My wife and I also use it to watch movies in bed. Interestingly, my typing accuracy is better with this desk than it is when I'm at my regular desk.