"Climb The Ladder"...

Warm-up 5 minutes at 5-6 intensity
Then: Pyramid Intervals
Alternate sprints of 8-10 intensity with rest periods of 4 intensity

10 sec sprint, 50 sec rest 
20 sec sprint, 40 sec rest 
30 sec sprint, 30 sec rest 
40 sec sprint, 20 sec rest 
50 sec sprint, 10 sec rest
40 sec sprint, 20 sec rest
30 sec sprint, 30 sec rest
20 sec sprint, 40 sec rest
10 sec sprint, 50 sec rest

Then: Cool-down 5 minutes at 5 intensity

4.46 miles
130 calories

Brutal.

Similar to the HIIT of the beginner's program, ladder interval workouts alternate periods of intensity with easy peddling. The difference is that each interval is a different length. The hard intervals gradually increase, while the easy-effort intervals decrease.