Try this 4-minute HIIT workout. Do the first 6 exercise for 30 seconds each, then finish with 1 minute of burpees. Add another round or two if you're feeling good!
30 seconds high knees
30 seconds of squats
30 seconds of jumping twist
30 seconds of hip dips
30 seconds of Russian twist
30 seconds of toe taps
1 minute of modified burpee