Austin, Texas
Credit: Kenneth Jones / Alamy

As the steamy summer temps finally dip in Austin, Texas, take off on the dozens of trails along its gurgling rivers and creeks. On the six-mile City Park Trail, you'll negotiate roots and ledges on singletrack that runs through Emma Long Park. The beginner-friendly McKinney Falls Homestead Trail has great whoop-de-dos. [Pick up a rental bike for $38; bicyclesportshop.com]