My take, I don't think there's any magic bullet.
Being religious about hand-washing and hand sanitizer, not touching any public surfaces with my bare hands if I can help it, and not touching my eyes or nose (which pretty much goes by the wayside on the bike, see the thread about vasomotor rhinitis
).
Sunshine and fresh air. (Vitamin D and staying out of environments where the virus replicates easily, for those who believe that if the Mayo Clinic can't explain something, it can't be true. But my personal opinion is that it would be surprising if there weren't more factors at work there.)
Think really hard about signing up for any races until after the flu season peaks. Light exertion is good, the sustained hard efforts required for training suppress the immune system. This is probably the toughest one for most people here. 
On the "it can't hurt" front, I've started taking elderberry extract. I actually started it after I caught my second cold this fall (training for two big events
), and the cold vanished almost immediately. Now... that's just as likely because it was only a slight mutation from the first cold I had and my immune system was already on top of it... but as I said, it can't hurt, and it's possible it was why I got over the cold so quickly.
Plenty of fluids and foam roller work. I don't really have any idea of how the fascia and the immune system are connected, but I know they are connected, and anyway, it's good for me on a strictly physical level (in the sense of "physical medicine" physical).
(And, as I said before, if it had been completely up to me, I'd have got the H1N1 vaccine and skipped the seasonal flu shot.)
Last edited by OakLeaf; 10-29-2009 at 06:47 PM.
Speed comes from what you put behind you. - Judi Ketteler