I recently got back from vacation in Colorado (sorry for the lack of posts).  My family and I drove all over the state.  The first nights stay started about four thousand feet above what I'm used to (1300 feet).  Over the duration we experienced a few altitude effects.  Started with dizziness, then headaches, then just overall fatigue.  We're just now starting to get back to normal.

Reading some literature on the state, it said some interesting things.  In higher altitude, a golf ball flies 10% farther, water boils at a lower temperature, etc.  I'm sure there are a bunch more.

A few more interesting Colorado facts