Share a 2K Row
One partner places a 15# plate on their partner's back, then
The other partner holds a plank position as long as they can during that run, then the two swap out.
Share 150 Sit Ups
One partner does max Squats with 95#/65# while
the other does a 100m Waiter Walk with a 50#/35# DB.
Partners do a relay run, swapping out 100m x 4; (each partner doing two runs).
Modify weights as needed/sane. Singles will have a modified (fun) version of the same work piece.