My Christmas gift to the forum. You would be hard pressed to find a quicker, easier thing to make. I was sorting some scrap when I had an ah-ha moment that I am sure is not original.
Cut out on the tablesaw and cut the slot just undersized. Plane smooth (also makes slot fit snug) and chamfer edges.
Slide together and PRESTO! A phone stand.
The first one went from "ah-ha" to pictures in about 20 minutes. You could probably make two at a time ;-)