Every once in a while I get stuck on a treadmill and typically when I do it's for a base run so there's not much going on. While I enjoy listening to podcast its helpful to have something workout wise to look forward to, which is why I usually toss in a few pick ups. Below is my "goto" treadmill workout, it's nothing fancy but it's effective and makes me feel better about my time spent there.
10' chilling/warming up
Main Set x4 (but repeat as often as needed till the workout is done)
- 1' @1.0mph faster than your normal pace
- 4' back at normal pace
If I'm running at 6.0mph and at a 1% incline then during the pick up I bump it to 7.0mph and then drop it back to 6.0 for the 4'.
(20' set/30' total workout)
That's it, a quick 30' workout and then I'll typically spend time in the weight room or stretching out after this.