Fun Friday: Staying Cool

It's time for a fun friday again. I'm not sure when the last time we did this, but it's been a while. I've been in europe all week where it has been warm. But I've heard that its been steamy in NYC where I am headed this evening. So with that in mind, how do you keep cool when the temps reach 100 degrees and it feels like a sauna outside? The obvious answer is air conditioning. But I am looking for other options. I like to go for a bike ride in the early morning, like 6am, when its still bearable out, and I also like to take a walk along the hudson river in the evenings where there is often a breeze when there isn't one anywhere else in the city. How do you stay cool when it gets hot outside?