typical warmup plus 50 more back extensions and 50 parallel leg raises

I made this one up on the spot:

4 rounds for time:
500 m row
50 double unders
10 30" box jumps
5 burpees

21:51

Only had one round where the double unders gave me a problem, other than that, was able to string a whole bunch together and got all 50 unbroken in round 2. Probably should have added something else to this, but seemed to have a good balance of aerobic and anaerobic components.