90/90
90 seconds of work, 90 seconds of rest. When you get this much rest, your work intervals need to be tough. GO ALL OUT.
Mark off a distance of about 100 yards. (You can also do 100 mountain climbers as a running substitute.) Start each 90 second round with a run out and back. When you get back from the run, finish the round with as many reps as possible of the exercise for that round. After 90 seconds, rest 90 and move to the next exercise. Repeat for 9 total rounds.
Round 1: Burpees
Round 2: Squat Jumps
Round 3: Jumping Lunges
Repeat for 9 total rounds.