It is really hot right now, and I thought I'd share a method I use to keep cool at the racetrack.
Get a small 6-pack cooler and fill it with ice. Pour in: 1 regular bottle of rubbing alcohol, 1/2 bottle of the green (menthol) rubbing alcohol, and 1/2 bottle of ammonia spirits (about 1/2 to 1 ounce). Add enough water to make it slushy so you can dip rags in it.
Dip in a rag, wring it out good, and wipe down your neck, face, arms, and legs. You can wrap the rag around your neck after that. Re-dip as needed.
Basically, the alcohol evaporates very quickly and cools you down faster than your sweat can, especially when it is very humid.
You may have to go to the pharmacy counter to find the amonia spirits (aka spirit of amonia).
I learned this trick at Suicide Circle Speedway from my buddy "Strolin" Jerry Nolan.