A burpee workout variation I like: you do a set of exercises (say, 20 squats, 100 mountainclimbers, 20 crunches, etc...) but for every minute it takes you to complete the workout, you have to do 4 burpees. So you set a timer to 1 minute, start your workout, at the 1 minute ping you stop where you are and do 4 burpees. Then you continute with your reps.
It hurts so much after a while but stopping and whining will just earn you another set of burpees