Dang 2.5 hour long workout!? Holy cow!
Some random things I can think of. (Without knowing how long your workout is)
Do a cardio rotation. You say you get bored doing the same thing, maybe do 15-20 minutes tread, then switch to a bike, elliptical, or the moving stair stepper, which my gym has, and keep switching for as long as you're waiting. That way you are still doing beneficial cardio, but breaking up the monotony.
Extended stretching pre and post workout
Can you add an extra set to the important exercises your doing?
Throw in something like drop sets, rest-pause into some exercises to eat up more time. This is especially easy with dumbbell and cable exercises. I sometimes do the "run the rack" system. I do it with dumbbell laterals frequently. Start with the weight you can do about 10 with (which for me is 25lbs) do 8-10 and set those down and immediately grab the next smaller weight do 8-10, then just work down the rack (I go all the way to 5 pounds). I actually then go back up to 25. It really, REALLY works your muscles, just like you are wanting to do anyway.
Maybe get your husband to do a superset or two to speed up his own darn workout
Just once or twice go over to the guys and ask if he(they) want you to spot him(them). If not for anything except being fun and funny.
Do you do warm up sets? If not, maybe warm up sets before your working sets before your main exercises. (Beneficial in more than just killing time).
Slow reps. Sometimes on arm exercises, I do the last set super slow. like 4-5 seconds on the contraction and the relaxation.