Five days a week, for three weeks, perform;

Push-ups (20s on, 10s off) for 4 minutes
1 min rest
Abs
1 min rest
Air squats
1 min rest
Burpee

To get a benchmark before starting the challenge, do as many unbroken reps of each movement as you can, with 2 min breaks in between movements, and note the result down.
After the challenge, do the same thing, compare the results and note down the huge improvement!