Something I came up with a while ago was the 100 Burpee Challenge, that is to do one hundred reps in a single unbroken set.
In doing this I used variations of the burpee, including the squat thrust, both with and without pushups.
In the following video, I hit 100 squat thrusts with pushups in that single set. It took me 7 minutes, 38 seconds to do so. This was my second time achieving this mark and I did it in a slightly shorter time than before.
I’m finding that this progression and challenge, with several variations used, is great for conditioning without needing any equipment or spending a whole lot of time.
Find more similar ideas inside of The Ultimate Guide to Bodyweight Conditioning.