Here's something I do when I'm either powerwalking, running in the forest or running on the treadmill at the gym. I usually run at the same pace of the song that I'm listening to, and when the song changes, I adjust the pace I'm running at to match it up. This makes the exercise more fun and it helps motivating me to continue exercising. Right now, due to the beat, one of my favorite songs when I'm working out is "Outta My Head" by Ashlee Simpson (ft. Timbaland).