Hi featherweights... I'm a returning 3FC member from a couple of years ago; I have about 20 pounds to lose and I was hoping for some workout tips!
I am a notorious creature of habit and I like to do more or less the same thing every day or every other day. Right now I am biking to work about every other day, and getting back to going to the gym at least a few days a week. At the gym I do 30-35 minutes of elliptical (interval training), and I trade off abs and glutes (situps etc., other ab exercises on the mat, abductor, adductor...) and arms (free weights) every other day.
I've read that doing the same thing for a workout all the time can make it harder to lose weight and that adding variety can help. But I really don't like trying new machines, especially because I have bad knee joints and I've found that on the treadmill, anything tougher than a fast walk (jogging, running) will end in joint pain for me. I've tried the rowing machine a few times for a different style of cardio but it always wears out my heels and my hands.
Anyway, can you recommend some good exercise tips? What works for you?

I've been doing elliptical and bicycling because there's no impact. I can't even do lunges because my knees sound like popcorn every time I try to bend them while I have weight on them... I'm not sure if it's something that I can work to improve or not; I think it's genetic to some extent at least (my mom's sister also has bad knees).

I've posted something like this dozens of time. I have dumbells and ankle weights on the coffee table in the living room. I can do hammer curls during my favourite TV show. Leg raises during commercials ...