Just as an aside, it can be tricky to work isolation lifts (like curls) into complexes because they'll generally limit the weight you can use for the bigger movements, unless you do something like double the amount of reps with the bigger stuff or use some "body english" to move the curls.
I totally get that working curls with a partner is an awesome thing, but maybe swap it out of that complex for an upright row or high pull. (Just a suggestion)
"I go, you go" sessions where your only rest is during the other guy's set is always a killer and works great for really blasting any one exercise.
CT Fletcher's style of "keep the weight moving using any means/ugly form necessary, first to quit loses" has its merits, but is also an easy way to tweak something and open yourself up to injury.
Dan John has discussed a bunch of challenges in various articles.
Last year (and intending again this year), we did a little 365-rep challenge for New Year's. 365 total reps, combined from one upper body and one lower body move (180-185 total reps each). Maybe give that a go and see which guy finishes first.