My son and his buddy came up with this: load BB to 50kg (110lb) powerclean, front squat then drop bar.
They did 40reps alternating so they had a short rest. This was done after Squatting, before the rest of their workout.
My son,Joe, then decided he was 'going for it' next workout; he did 50kg, powerclean to front squat, as singles (i.e. dropped the weight to floor after the front squat, rest if needed then repeat) without his buddy alternating he managed 50 total reps in 14mins 26 seconds.
I was quite impressed! For info Jo is 6ft 4inch and weighs 15 stone (220lb)
Seems to me to be a pretty good challenge (I know I couldn' do it).
Other ideas have been 25m jog LIFT, 25m jog back. alternate with buddy and complete 25-50 'reps'
LIFT= 50kg power Clean and press, or 115kg Deadlift.
They certainly enjoy these routines.
Lesson here is you dont need special equipment to do conditioning.