I warmed up for a while and then went upstairs to do this WOD
I didn't have much time, and did a good WOD last night of rope climbs and high rep KB swings.
I did 5 rounds of:
30 GHD Situps (I used the stallbars and hooked my legs into them while siting on the plyo ball - very similar in ROM and movement)
30 Back Extensions (I didn't want to bounce out of the bottom but rather squeeze and contract out and to NOT hyperextend my lower back as well.)

Good stuff. I just kept on going. I usually would do 20+10 for the back extensions and the GHD situps varied per round and the sets got a little smaller as the sets went on. I would normally do 10 at least if not more like 16 and then rest a couple seconds while adjusting and get back into it.
Fun stuff.
I then stretched a bit and then worked on walking on my hands and kicking up to control a bit.