It is an easy project if you have access to a miter saw, and will take only a few hours to complete (most of this time is waiting for glue/paint to dry).
I had some leftover 2" diameter PVC that I cut it into 5" lengths on my miter saw set to cut at a 25 degree angle. I arranged the cut pieces into a 4x3 honeycomb, and then glued them together with PVC cement. Some spray paint and a plywood back completes the project.
Step 1: Cut the PVC
All the usual cautions about using power tools apply here. The miter saw can be dangerous. Know where your fingers are before you pull the trigger.
Before doing anything, reverse the blade in the saw. The rake of the teeth in the saw blade makes the blade want to "grab" the round pipe and spin it. If you reverse the blade, it will cut using a grinding action and it does not have the same tendency to grab the pipe. (Use ear protection for this. It is loud)
Set the angle on the saw. I used 25 degrees, which seems like it is enough to keep things from falling out of the pipe.
Start by cutting the end of the pipe at an angle. Hold the pipe tight while cutting so it doesn't spin. Rubber-fingered gloves would be a definite help. Clamping it to the saw guide would probably be a good idea.
I cut the pieces into 5" lengths. It works for me, but might be a little too long for some things. When you have decided the length you want, clamp a block to the saw guide for uniform cuts.
If I were to re-do this project, I would use a marker to draw two lines down the length of the pipe, one line 180 degrees on the other side of the pipe. When cutting, align this line with a line on the end stop. This will help to insure that the cut ends of each piece are parallel to one another. The lines can also be used to match up the pieces while gluing.