first of all, highly unadvised to do P90X during a heat wave. second of all, also as highly unadvised to do P90X after having all-you-can-eat Korean BBQ. with that, onto my summary.
Core Synergistics is just that, working the core, and working it all at once. given my above preface, i was unable to finish the entire video. stopped with a little more than 20 min remaining (a 55 min workout, after warm-up). it has some pretty intense holds and moves. includes some push ups and lunges, etc. this one pretty much wraps everything together into one. it really does get your core (everything between your chest and knees) fired up. i was sad i couldnt do the rest of the video, as there were some pretty challenging moves (which looked like a lot of fun, and which i probably could have done, given more favorable conditions). you'll sweat a ton from it, at least i did. and i love working the core.
i think its pretty deceiving that this is done during the "recovery week". there is nothing "recovery" about Core Synergistics. BRING IT.