Do you even have a favorite cardio? I really used to pretty much hate all things cardio. I like the weight training and used to tolerate the cardio because I knew it needed to be done. Sometimes I can find one I tolerate more than others, sometimes it's just the specific results I like and deal with it. Recently I've found some I actually look forward to, but more on that in later issues. There are so many choices, and I think I've tried them all. Classes, dvd's, cycling, walking, stairs, ellipticals, and even running. They all have great benefits, some work parts of your body better than others. Some are easier on certain joints than others. Some you just hate less than others :)
Are you a class person? Most people either love classes or hate them. I don't love them, but if you do, there's a lot of energy and support there. There are so many options: from dance to spin, from body pump to yoga. Find your favorite instructor and type of class and jump right in. You'll have fun and might make a few new friends too!
Not a class person? Still like the energy of dance, step or other aerobics? If you prefer to go it alone, you can rent dvds, check them out at the local library, search youtube, check out donated ones at thrift stores, even borrow a friends to see if you like it. I prefer the try-before-you-buy option because you never know whether you're going to like it enough to stick with it. The benefit of this is you can do it in the privacy of your own home, any time of day or night that works for you.
Machines? Bikes, Ellipticals, Stairs and Treadmills oh my! Of course bikes will focus on your legs, stairs will focus on your legs and butt, ellipticals can be whole body trainers if you use the arms too, and treadmills give you the option of a walking or running program, flat ground or incline. Pick your focus and what works best for you and hit the machine of your choice. Switch them up, even split your time between 2 different machines for variety and maximum muscle confusion.
Take it outside! If you don't have a machine at home, or access to one at the gym, you can bike, walk or run outside. You can climb stairs anywhere they have them. I haven't seen elliptical options, but that's just about the only one that doesn't translate!
And can I suggest you check out HIIT (High Intensity Interval Training or sprint interval training) as part of your cardio protocol. 20 minutes max for an all day calorie after-burn. Can be done with any type of cardio, and there are different kinds. NOT to be done on weight-training days and generally not more than 3 times/week depending on the type you choose.
REST DAY! Take one! You will get better results if you do...