Step 1: Stuff you need
Purchase the following:
- Metal bookend
- Non-slip mat
Step 2: The ugly side
You can reposition the mat many times -- the tape peels off easily, even after being in place for months (in hot climates YMMV).
If your phone or gadget is large or heavy, you may want to tape some thick card across the center as reinforcement.
Step 3: Bend it. No, bend it more.
As you can see in the picture, mine is about 60 degrees from horizontal.