Boy, I hate to be the stick in the mud, but tinfoil (aluminum foil) isn't a very good shield against RF energy. It will stop the electrostatic component IF it's grounded properly (and how many people who wear the AFDB bother to run a piece of braided wire to a ground rod?), but it won't do much to the electromagnetic component.
For that, you need a ferrous material -- such as an old steel army helmet.
Take the helmet and line it with copper tape. Carefully solder a braid to the tape AND drill a hole through braid, tape and helmet; run a screw (with star washers) through the hole and tighten securely. Now run the braid to a good ground.
If this contraption is too heavy, rig up a sliding support across the ceiling to permit freedom of movement while wearing. One of those horizontal dog runs (available from K-Mart) will do nicely.
Of course, if you're REALLY serious, you could put copper cloth in the walls of your house and in the door panels of your car, but you'd also have to spray the windows with gold film (and ground it), unless you choose to use metal blinds (also carefully grounded from strap to strap with a piece of braid).
Just thought you'd like to know.