I know the importance of a good exercise routine in any weight loss plan. Right now I try to do 30 or 35 minutes on the recumbent bike at the gym at least 4 days a week, but lately it's gotten a little boring. Plus I'm not sure if the gym at my college has recumbent bikes, so I'm wondering about other options.

My main limiting factor in mixing things up is that I have weak knee joints (always have), so activities like jogging, doing lunges, and even just walking up a lot of stairs can cause my knees to pop/crack audibly and be very painful. So I'm wondering about some other good fat burning/cardio workouts or gym equipment that won't put a lot of stress on my knees... any ideas?

Elliptical's and like machines are great if you want to avoid impact! A few months ago I got horrible shin splints from jogging outside and on a treadmill. My moms personal trainer recommended I stay on the elliptical and machine alike to give my joints and shins a rest. So, I did for a couple weeks straight. My legs never hurt during or afterward and I still got a great workout! Look for any equipment that you can kind of lock your feet into and has a rolling-stride smooth movement.

Good luck! I hope your gym has something that helps!