There's different stuff you can do on the elliptical—a machine at a gym I went to gave me instructions to lean forward, or lean back, or pedal backwards on the machine. You could try those and also try bending your knees more. That'll help work some different muscle groups. Also your muscles will probably become more efficient for that specific purpose, so you may not be burning as many calories on the machine as you used to, or as many as it says.
I like to do some lightweight dumbbell exercises when I'm watching TV. I just pick up the 3 lb or 5 lb weights and hold my arms out to my sides, or slowly lift and slowly drop them, or curl them forward in front of me, or do yoga movements, lifting them right up above my head then down in front of my chest, then out, around, and back up. I try to keep it mixed up and just do whatever feels good. I don't use anything heavier because I don't want to have to worry about hurting myself if my posture is a bit off or something.
Another thing I'm going to try doing more of is going to the pool. I did that this weekend as was reminded how tired I get just from bobbing around, diving under, and having fun (not even doing laps). Even treading water or floating means you're making constant minor adjustments and the end result is exhaustion, which in my mind means calories burned.
Even better, though: Go out and try some stuff. I know it's annoying when you can't figure out how many calories you've burned, but the fun is worth it. Do some rock climbing or go to a trampoline park or go hiking or snowshoeing or something.
I bet if you went and did something new every week (or every month), you'd figure out pretty quickly which muscle groups you've been neglecting, if nothing else. ^_~