When I'm back in the rear with my unit, we do 30 second sprints followed by 30 seconds of walking, for 10 minutes, then walk for 5 minutes. We then do another 10 minutes of the 30/30s and then stretch.
The same day the following week, we sprint for 30 seconds, walk 30, sprint for a minute, walk for a minute, sprint for 2 minutes, walk for 2 minutes, sprint for 4 minutes, walk for 4, sprint for 7, walk for 7, and then work our way back down, followed by stretching.
Both of these are pretty good smokers that suck while doing them, but you feel invigorated after you're done. Sick, I know.