Step 1: Parts List
1 wire mesh pencil cup (with mesh bottom)
1 piece of 1/2" PVC pipe scrap cut to length of cup
2 medium length rubber bands
2 hose clamps
The cup cost $1 and the clamps came in a variety pack of twelve that also cost $1. The elastics came in a wonderful bag labeled "One pound of rubber bands" (also $1) that I have used for many a project. I already had the 1/2" PVC scrap laying around, but even if you buy a ten foot length it will only cost $1.50. Cutting the PVC is a real pain unless you get some ratcheting pvc cutters, which I highly recommend. PVC pipe has so many great uses (it's sometimes call "the Tinkertoys for adults") that these cutters are a wise investment. Get them for a scant $2.49 at Harbor Freight ToolsHarbor Freight Tools.
Step 2: Bottom Out
Once the bottom of the cup is removed, check the edge for straggling bits of metal that someone (like you) could cut their fingers on. Get some needle-nose pliers (I used the Gerber multitool that I always carry) and pull them off. I'm all for expending blood and sweat on a shoot, but tying up loose ends like this will save you some.
Step 3: Make Your Marks
Step 4: Cut Holes
Step 5: Add Clamps
Step 6: Insert Pipe
Step 7: Rubber Bands to Finish
And that's it! Run your mic through the center of both pairs of bands, attach the mic clamp to the PVC, and you are well on your way to cleaner sound, unmarred by any noise your boom op may make as they reposition themselves. The only thing else I might do is spray paint the PVC black so the whole thing matches and looks more professional.
Go check out the new, improved version!