Essentially, I had a 5-minute "rest" interval of one pace and then did a 3-minute "work" interval at a faster pace. When I got to my next rest interval, I picked up my rest pace, when I got to my next work interval, I picked up my work pace. I have found this strategy not only provides a good workout but keeps treadmill running boredom at bay.
The end result:
4.06 miles with an overall pace of 8'26"
I am very happy with that! And check out my splits. I broke an 8-minute mile at the end and truly incorporated negative splits along the whole run.