mad_jock, You can't "catch" chickenpox a 2nd time. Shingles, which is a reappearance of chickenpox, comes from "latent" virus hiding in your cells from when you first got chickenpox.
Shingles is terribly unpleasant, but avoiding people with chickenpox doesn't help. Shingles comes back from latent virus re-emerging, so the best you can do is to keep your immune system strong, and to go on anti-virals as soon as you suspect it's coming back up.
(This is a separate issue from adults catching chickenpox for the first time. That's terribly unpleasant too, but there's a vaccine to guard against it now.)