When I was getting headaches 30-50miles into a ride, I had a few "duh" moments.

I usually drink tons of coffee in the morning, but I had been skipping it before a long ride because I didn't want to pee. So: caffeine withdrawal. Started doing a shot of espresso and ensuring my first couple of Gu's were caffeinated.

Strange hairdo. In my case, I thought I was being clever with the pigtails. Took off the elastics, and felt my head release. Who knew?

Then, I keep a baggie of Vitamin I and electrolytes with me. I try to take one of each every 50 miles or at the first sign of headache or cramping.

-- gnat (now quite pleasant to be with on a ride!)